NumPad shortcuts are handy for WM/tiling purposes, as well as for some matured apps which KDE itself doesn’t lack of. There was an open ticket for Kate, which was closed as “resolved unmaintained”.
Unfortunately, NumPad shortcuts are only available in system setting, thus as global shortcuts. Although, situation within apps improved over time. First they were not being recognised at all in app settings, then accepted non-correctly, recognised poorly and finally accepted correctly e.g. Ctrl+Alt+Num+4, but still they misfire(do nothing). So one might get impression that underlying work is active.
The lack of NumPad shortcuts deprive users of many additional shortcuts when modifiers are involved(~70). Their status is undetermined at the moment. Here is some unconsistencies of present behaviour:
1. Krita - recognise Ctrl+Alt+Num+4 as Ctrl+Alt+4
2. KdenLive - recognise Ctrl+Alt+Num+4 as unique only if Ctrl+Alt+4 is not set, otherwise use Ctrl+Alt+4 set for both shortcuts
3. KDE Gear apps - recognise Ctrl+Alt+Num+4 but do nothing, but if Ctrl+Alt+4 is set it acts for both
4. Non KDE apps - mostly recognise Ctrl+Alt+Num+4 as Ctrl+Alt+4