The primary selling point is speed. If you want to practice "All The Things You Are" in the key of E-flat at 140 BPM with a Bossa Nova feel, you simply open the file, type the new key, and change the tempo. It takes 10 seconds. Doing this from scratch requires typing 64 bars of complex chord changes.
This is where the "Band-in-a-Box Real Books 13000 tunes link" comes into focus. It represents a marriage of the contents of every volume of the Real Book (6th Edition, 7th Edition, and all the supplemental "Real Books") with the automated intelligence of BIAB. band in a box real books 13000 tunes link
Most of those 13,000 files are user-generated. Some are masterpieces; others are garbage with wrong chord changes. The value isn't the link—it's the curation. The professional musician does not need 13,000 songs. They need the right 300 songs with perfect voicings. The primary selling point is speed

