And that distinction really only exists for instruments like the guitar that can play the same note on multiple strings. Piano music on staves is already very s

And that distinction really only exists for instruments like the guitar that can play the same note on multiple strings. Piano music on staves is already very similar to a piano roll, at least on the y axis. You still have to learn the notation for different durations (the x axis), but there's not much mystery over how to physically play the notation on a piano, other than some potential for tricky fingerings. There is also fairly standard staff notation for fingerings, both for piano music and classical guitar music (in my experience, it's much more important for the latter).