Donny, with all due respect, I think what you're missing is that you expect (demand?) that everyone justify everything they do. Sometimes people just do things because they want to, no reason or justification needed. As Bachus said (or implied), just because you use one thing doesn't mean you have to exclude everything else. What's wrong with having a variety of tools in the toolbox? Different tools for different jobs (or different tools for a different approach to the same job). Some people just like to experiment; like having a car collection; you don't collect them because one is
better than the other; you collect them because variety is FUN (I could have used a wife/girlfriend analogy here but chose not to ).

I have an old (2015, I think) copy of BIAB and find lots of fun uses for it, such as inserting it inside REAPER or generating lead sheets or extracting chords from a midi file, etc., etc. I think it's a really clever program that (frankly) with the exception of 'live playing', is nearly as flexible and useful as an arranger (and a hellava lot cheaper). JMO.

chas