I use BiaB to:

A-the MIDI side
1-input different chord progressions to see how they sound in original songs
2-play with styles for original songs
3-drag and drop the above 1+2 into my DAW
4-practicing soloing my guitar or wind controller
5-practice my sight-reading. I will randomly pick a song from a fake book, load the appropriate Norton fake disc, then sight read with either my guitar or wind controller. BiaB, a fake book, and the companion Norton fake disc are a natural combination.
6-try to duplicate problems to help others
7-to make backing tracks to help my students
8-to print out either chord or lead sheets
9-when in a writers block I will use the melodist or soloist for inspiration

B-the RealTrack side
1-to create backing tracks for some of my jams and/or songs
2-to create backing tracks for others, including students
3-to add a track or two for my MIDI songs

I do not use the VSTi version of BiaB.

Life is short so make sure you spend as much time as possible on the Internet arguing with strangers.

64 bit Win 10 Pro, the latest BiaB/RB, Roland Octa-Capture audio interface, a ton of software/hardware