James, for what this feature is designed for....having the MIDI of the song you are going to play is FINE...it is kind of a kaoroke.
But it would work fine at home or elsewhere for someone to sing with.
This is not a live PRO gigging musicians tool. Well, it could be used in a special situation...how many here can sing songs from Phantom of the Opera??? ON KEY??? Not many...so you see it may have some applicibility for anyone.

One other question...since I am out of sync with the Korg PA3X..did they fix the TONS of bad sounds coming forward on the PA3 that were on the PA2?? That's one BIG reason I sold mine???
I sent 3 pages of bugs in the sounds to Korg, never heard a word back.