There might be a market for the SMF, then the SMF done in audio with backing vocals, and maybe even the BV's alone. This might offer the best flexibility (that way, you mute out what you want on the SMF, record it as audio, then mix the BV track in...).

But for me personally, I stay away from audio backing at the moment, because there's no way to put Markers in. That one feature, for SMF's, totally opens up the way you can use them. You are no longer hog-tied to a particular form, and can extend or shorten your song as needed. Until they figure out how to do this with audio backings, I'd rather give them a miss.

Mind you, it might be nice to have some Kurzweil sounds or VSTi's beefing up the backing for sounds they might do a hair better than my G70 (without having to tote them to the gigs), but I can make do for now.

BTW, I don't disagree with people using audio. You are right, in some ways, the end result can be quite similar to SMF's. Probably what gets me the most is COMPLETE audio backing tracks, leaving next to nothing but the melody for the player. That's about where I draw the line! The Lord gave me two hands...!