So what about the "sound quality" of MIDI?

What people mostly worry about when it comes to "organs and MIDI" is sound quality. However, MIDI actually has little to do with sound quality. MIDI is simply a system of communication that permits communication between electronic musical devices.

MIDI, however is able to control things that do make sound. It can communicate with "real-pipes" or "high quality digital samples". In some cases it communicates with both like it does in a hybrid organ.