BIAB has amazing sounding tracks that you can manipulate in many ways, but I think because they used a more universal linear approach in their "Real tracks" (the muscle behind it all) it is very hard to actually create a complete song. What I mean, they do not have a traditional approach like arrangers do, with parts for Intros, Variations, Breaks, Endings only imitations of them... Created songs at times resemble looong snakes because it lacks proper "breaks", "fills" and "bridge" parts. It is possible to manipulate their tracks to make a tune, but not intuitive at all. Overall I think their software engineers are ignorant boneheads.(not musicians who record stuff for real tracks, musicians are actually awesome) It is a "feature creep" 32 bit program that looks like something from late 90s, and feels that way too. But in reality there are not too many choices if you want to make backing tracks that actually sound good and not spend weeks if not months in studio and they take full advantage of that refusing to modernize their stone age program to make it robust and user friendly.
Having said that, vArranger (hi Dan) has more traditional approach compared to making backing tracks. It is a MIDI only program. It is very stable and fast, uses many style types from different hardware arrangers, but has a hefty price tag and many shortcomings.
One of the best approaches into creating complete ideas for tunes fast were first introduced in Yamaha QY sequencer series (20+ years ago). Where you can mix various parts/genres re voice them on the fly etc. Yamaha, a few years back came out with software arranger as an app sadly for ipad only. It took best features from hardware sequencers and added many new ones. Sadly it is for ipad only and uses only "in house" Yamaha styles many of which were taken from 20 year old sequencers.
Since Bandlab is a Musician based platform, not just Cake... maybe Meng and his Magic crew should consider something like an arranger for creating backing tracks or as a scratch pad for song ideas that would resemble more traditional, hardware arrangers.... Just thoughts out loud :)