I really like that idea of playing music to an instrument so that it can learn how to sound better while you are doing something else. Whether it's true or not, it's a beautiful image. Now I wopnder would it make any diffeence what music it was exposed to. Could youirreparably damage your instrument by playing (you name it, I'm not starting a fight here) to it?
Anyway it certainly seems true that an instrument that has been played a lot seems to sound better, and play more easily.
As for capos, Kyser may be ugly, but they are the only capos I've ever come across where you can shift them around in the course of a tune, and still be in tune with other people.