Originally Posted by cricket3
Also, I don't play guitar, but i wonder if learning the chords and progressions would serve the same purpose? Or even ukelele or something like that?

Piano and guitar are the two main instruments that let you pick out notes and play chords (or both at the same time), and of the two, my opinion is that guitar is the far better teacher of how scales and intervals work, because there are no black keys to get hung up on... all semitones are treated equally.

Of course, it's also entirely possible to pick up a guitar, look at some tablatures, and play passable music without ever learning a thing about how music actually works. So there's that.