The user is capable of swapping between Desktop and Sketch modes, and may choose to use the tablet interface on a laptop/desktop. When Sketch is used, it does not support keyboard shortcuts, even for familiar tasks such as undo/redo/save etc.
This is going to be tricky -- all the shortcuts are bound to KoView and the whole kxmlgui pyramid of of shortcut definitions. It'll be ages, or at least until we merge the mvc branch, before we have a fix.
I'm sorry, we had to drop support for the sketch and gemini variants of Krita because with the existing code, we couldn't make it work with Qt 5.