I think this is a necessary feature, especially when people who do not know the language on the physical keyboard need to use the machine. Now that 'kvkbd'(qt4) is old and KDE has no native on-screen keyboard application, it would be nice if there were one as part of the Accessibility feature set, using the 'qt5-virtualkeyboard' framework.
I've begun using the wayland session, and I see that there is a 'Virtual Keyboard' available.