RealBand will read and load BIAB files
But be careful because it does not read everything you do in BIAB. For example, your bar settings will not be restored in RB. And I cannot recall for sure but I think frozen tracks still got regenerated in RB but maybe I'm wrong and if so someone will correct me.
My only point is you need to think about what you will do before spending a lot of time in BIAB because if your next step is gonna be RB then some of that BIAB work may not survive the transition.
My work flow, because I have a DAW I greatly prefer to RB, is as follows,
1) create tracks in BIAB
2) export my tracks as individual mono WAV files with no reverb or panning applied
3) import those tracks into my DAW and mix them
If I find I cannot get exactly what I want I will open the BIAB file in RB and then try to selectively regenerate certain sections and export those tracks as WAV files to use in my DAW. But I avoid RB if possible because I find it to be cumbersome in my overall work flow.