Gig is slang for a live musical performance.

So if Dave doesn't want to use slang, so be it ...

BIAB is a very capable program, but not for live/stage play..

Here is an example how I have used it.

Lets say you have a new song you want to do, but are not familiar with it.. You can record the song from any source or download it from youtube , save as a mp3.. Load into BIAB, select analyze chords. It will show chords for the whole song.. Now you use these chords and select styles from BIAB.. making the song your own. You can also select audio instruments triggered via MIDI.. Save as a SMF or save as an audio file.
You can also print the score of the song you just programmed (without a single music ability) even in a fakebook form.

BIAB has a feature called conductor that vastly improves its play-ability live. Well I agree that most users that rely on it tend to create mp3's they use when performing there are many who are using it successfully to play live while playing melody on other instruments. If you go to the forums at pgmusic you will find hundreds of users that use it in all different ways. It diffently not as spontaneous as a good arranger but with effort will almost always produce better results.

BIAB Discussion