Russian
A very common question is: “I am a beginner, not a professional. Why would I need lots of tines?”
More notes give the instrument more possibilities, but many people worry that they also make it harder to play. That is an illusion. If you are following a method, you learn which particular tine to play at each moment; the number of other tines does not matter. If you are experimenting intuitively, more options make the process more interesting.
There are no special 20-key pianos that you have to start with. ;)
On a kalimba, the useful upper limit is mainly how far your thumbs can reach.