Actually, I hit this problem when I used ssh from my android phone to log in into a linux server, and I tried to use vim to edit some files.
It was a little bit... displeasing, although I could do everything which I could do from a normal desktop/keyboard.
Extension: There was a question, why it was displeasing if I could do anything I wanted. For example, typing
5j45| on an emulated keyboard on a touchscreen has a much lower information rate (between your brain and your device) as touching the intended character position on a touchscreen.