I agree with Herb.
I will add: learning about the structure of the song(s), experimenting with different chords, progressions, tracks, programming particular sections, partial regeneration, manual fusion of different styles, 3rd party instruments and elements, etc. etc.
To me BIAB was always more of a composing/learning tool, not a cover song generator, I only very recently started explore "Songs", just to learn how their structure is laid out in BIAB.

JJJ,
Stop lying to your aunt!
P.M. me, I will send you a Holiday card.