"Why not just use the RealTracks as audio? I guarantee a guitar RealTrack will sound better than your best VST synth trying to fake a guitar, for example..."

1. That's not so true of bass or piano, I find. (Guitars I do myself.) I have a number sampled libraries. Is the BiaB RealTracks acoustic bass better than a sampled acoustic bass triggered by MIDI? Often it is, not always.

2. More simply, with audio tracks I can't change my mind about instrumentation later on (do I want acoustic or electric piano?) without leaving my Logic workspace, going back to BiaB and remaking the tracks and reimporting them.

3. I can't manipulate audio tracks in the same way as MIDI. For example, since BiaB still doesn't do ritards, I have put them in in Logic, and Logic seems to handle that more flexibly with MIDI than with audio, especially in extended ritardando endings. More important, I can't tweak individual notes, and I do a *lot* of that when using BiaB tracks as the basis of bg parts in recording.