Comment by crtified

A small toy xylophone with each note painted a different colour works by the same principle of abstracting melody into a simple system whose mechanics are already mastered. That kind of device has given children a way to learn Happy Birthday (by simply going Red Red Blue Red Yellow Green.....) for many generations now.

The full challenge however is that "knowing how to play an instrument" in the musical context is a deeeeep, deep well, and that any musician is only as informed as their experience. Hitting-notes-in-order means you've just walked into the atrium of a potentially lifelong learning experience, no matter what the instrument.