learning mode with the keyboard

For the record, I am not saying additional "training" types of features would never be added. I'm just helping set your expectations as to the priority of this type of thing and suggest you'd probably get better results faster looking elsewhere. Features like this don't in themselves "take away" from score creation, but the time and effort spent implementing such features is time and effort does take away from the development of features that have more to do with score creation.

But when you suggest the free MuseScore and paid one, you're on the right track, I think. This sort of performance-oriented feature is really much more in line with the mobile app than with the MuseScore (the editor program) itself. So I wouldn't be surprised to see it added as a "Pro" feature there some day.

BTW, your example of the piano keyboard is a good case in point regarding the focus of the MuseScore editor program. Although I'm glad you find this feature useful for training purposes, that is not why it was added. It was added as a way of entering notes - so you can simply click notes to enter them if you don't have a MIDI keyboard. It only took a tiny tweak to the code to make it work during playback, so that didn't take anything from other development tasks that are focused on score creation.

Similarly, most of the playback features in MuseScore are intended primarily to help composers hear their works performed as intended. When it's easy to tweak them to make them useful for training - like adding the count-in option to the metronome feature - that usually gets done. Whereas what you describe - "score following" - is actually an extremely complex AI task. So it's kind of unlikely it would just be tossed in on a whim. Could be an interesting Google Summer of Code project some day though!