Rikki
There was a similar thread over on the PSR Tutorial Forum a couple of weeks ago. I was really surprised at the number of folks that still use BIAB. I thought I was one of the very few. I use mine either for quick backing tracks for the guitar or for quick auditions of new chord progressions, but when I play the arranger, it is strictly the arranger. The problem with playing the arranger to either a MIDI file or an MP3 is that it's like playing with a real band. If you mess up, you have to go at a dead run to get caught up, but if I am controlling the accompaniment in real time, I can adjust either the accompaniment or the melody or both to get everything back on track.
I think, as arrangers improved, interest in MIDI-only BIAB dropped off somewhat with the older crowd, but now the Real Drums and Real Tracks technology have caused a surge in interest with the younger virtual instrument crowd. Good for BIAB. They deserve it. They have provided a nice product thru the years. I don't use it all that much anymore, but I still would not be without it. I am still an old school stand alone hardware guy, so I am pretty much BAIB MIDI-only. The latency of the virtual stuff is just not for me.
Regards,
Ted