I see that with Make numlock on by default (!6788) · Merge requests · Plasma / KWin · GitLab Num Lock would be enabled by default.
In my case, I have a laptop with a keyboard that doesn’t have a physical num pad, but the manufacturer decided to allow using one when Num Lock enabled. The num pad keys are mapped onto some other keys that behave as a num pad when Num Lock is on, and behave normally when Num Lock is off.
The consequence of this change is that by default some numbers and letters won’t work as expected by default on my laptop because they will output other numbers and numerical symbols. Maybe the picture can explain it better:
I know this is the case of some very niche ten year old device vs general use case, but it adds to the whole picture.