The taskbar is slow if you are managing a lot of windows.
If you want to stash away a window configuration and go back to it later, you have to remember it, minimize all windows and open the ones you want.
With virtual desktops changing between layouts is one action. It also makes the taskbar itself easier to use, as each desktop has less windows.
That doesn’t mean the taskbar is not useful. It is simpler when layouts don’t have a lot of windows or are switched infrequently.
Sorry for the extremely late reply but I’ve been very busy. That said Virtual desktops, Activities, the default Taskbar are all a matter of what one is use to. I like multiple desktops cause I can keep two Dolphin windows on the Dolphin desktop and have any disk and or file editing software open there, I can open either Deluge, Emby, Solsuite on the Spare desktop, most of my other apps on the Applications desktop, my browsers and email on the Internet desktop. With things open on their assigned desktop I can just switch to what I want by clicking it’s Icon in Icons-only Task Manager or it’s Desktop in Compact Pager. For myself this works very well. Workflow is what one makes of it. It breaks down to what works for the individual using the system.
@jpgaubier see my above comment. Combining Activities and Virtual desktops would keep ALL the features of Actives and Virtual desktops and simple combine them.
now both of you take a read of @_sr 's first post in the thread.
I still believe that Activities and Virtual Desktops need to be combined and then maybe rebranded Workspaces. What I don’t agree with is messing with the Systray, everything that is running in the Systray should be available across all desktops rather they are Activities or Virtual desktops.
One of my favorite things about Activities (and Virtual Desktops) is restricting context switching. A side effect of that is that they hide things from you, which is desirable.
If you only use a single virtual desktop (another way of saying you don’t use them) and you have, say, 6+ windows open, it can be very annoying and slow to switch between them (even though there are many ways to do that).
If you use three virtual desktops with 2 windows in each of them, you can now separate windows in pairs of tasks, and you always know that in each virtual desktop, you can just Alt+Tab or Meta+1,2 mindlessly and you know you’ll always get the right window. You can just quickly move to another virtual desktop with two other apps that are often used in conjunction.
Activities takes that restriction of context a level further by focusing not on window switching, but on task switching. You can restrict the list of programs you see to only work-related applications when you’re on the Work activity, and leave distracting chat apps and other such things only visible to you during your Leisure activity, and other such things. And this is applied to entire groups of virtual desktops for each Activity, not just a set of windows.
While Virtual Desktops hide things from your current screen, Activities hide things from your current virtual desktops, just so you can better focus on what you are doing.
Hence why combining the features of both into one feature and getting to select how you want it to behave makes more sense. There are items in Activities that should be in Virtual Desktops and visa-versa.
In practical terms, how would you keep the ability to hide things from the currently visible group of virtual desktops if there isn’t anything a level above them to group them?
If you recreate the abstraction of “groups of virtual desktops”, you’d end up with Activities again.
The only way I can think of merging them while keeping this ability is by moving Virtual Desktop features a level higher. That would mean embracing Activities as the main thing, and having Virtual Desktops as a smaller part of them.
“Combining the features” sounds like a flat choice matrix that is powerful but hard to figure out for the user and hard to implement for the developer. The distinction between Virtual Desktop (organizing windows) vs Activities (organizing tasks) provides some preconceived scenario for the user and hopefully provides structure that limits the scope for developer.
Both features are imho orthogonal. Virtual desktops provide more virtual pixels - essentially a “software monitor” to place things. Activities provide a different context to the current desktop environment (widgets, task manager, favorites, …).
That is something for the devs to sort out. I honestly don’t care how it’s done or implemented as long as I can do the below.
If I want to limit the systray icons by activity / virtual desktop I can, but all on all enabled by default.
Still choose which activity / desktop particular applications open in or on. I have right now Applications where most apps open on. Internet where browsers, email, and messaging apps open on. Dolphin when Dolphin, disk utilities, video and audio editing tools open on(audio and video players open on Applications). Spare for things like Deluge, my solitaire game, Emby in Chromium, Emby Theater, etc…
The current has benefits depending on one’s workflow. Like when one member said they mainly use the taskbar for there workflow. It boils down to what works for the individual.
It is great to hear that Activities and Virtual desktop features would be retained. One idea for combining them and clarifying their relationship: Activities displayed on the vertical axis (as they are currently shown with Super+Tab) and Virtual Desktops displayed on the horizontal.
Yea the devs value their lives, and to get rid of either would be taking their lives into their own hand. 
To have better organized desktop. For example, you can link folders from many places to work activity (in future maybe to not allow only link files, but e-mails too?), you can place notes on desktop related to activity, you can have windows related to work on work activity. This make a way to faster use of computer.
What would really be nice is the ability to have separate panel widgets, default applications, default browser profile, and Dolphin places / bookmarks per activity. That would make activities worth using for me.
I have given multiple desktops a go since I last wrote on this thread; I’ve come around. I use them when I’m working on something that requires filling the screen, like updating my blog (Kate on 1/2, live browser preview on the other), and when the work is likely to take some time and I’ll want to do other things on my computer when I take a break from the project.
This might be slightly off topic (since it involves Firefox which is not a KDE app), but here’s a scenario that I would like to be able to achieve with Activities (I haven’t allocated the time to give it a try because I’m pretty confident that it’s not possible).
I would really love for the ability to be able to have “Work” and “Music” workspaces. Each workspace would (among other things) need to include an instance of Firefox with multiple tabs open (work related tabs in the “Work” workspace and music related tabs in “Music”).
I would like to be able to reboot my PC (updates) and retain my workspaces complete with my Firefox instances restored as they were. That would be a dream scenario for me.
You might be able to do that if you use different firefox profiles on the activities.
And then within each firefox profile you edit the start page to contain the different pages you want to open, or even just save and reopen the session for each user.
As @bedna said Firefox profiles are a nice way to completely separate different FF environments. You can manually create desktop entries and pin those on the task bar of the different activities.
There’s also a handy FF extension named Window Titler, which makes it easy to target a specific FF window with a kwin rule (e.g. to force it on a certain activity).
Search for nepufox or similar script. Next, set nepufox as default browser. Nepufox reads current activity id from kactivityd via dbus and open/create profile with this id. You must only (for nepufox) read your current profile name and activity id and change that in script.
Thanks so much @bedna @Schlaefer , your recommendations have not only opened my eyes but also drastically improved my quality of life! 
@slawomirlach I did an internet search for “nepufox” but I didn’t get any results that seemed relevant. Maybe I am missing something? Is there a direct link to that project? Thanks!
I don’t agree with it. The right thing is to fix the defects and keep both. I am a “activities”, and also “workspaces”; For me the two essentials. So don’t help my workflow be destroyed because you don’t use it. There are those who use it.
That may well be but, they’re conceptually different and, looking at the post made by Gleycon, there are folks who rely on the this conceptual difference for their workflow.
BTW: @Gleycon:
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