And yet BIAB does actually have a New Age midi style that's described as rubato, AWAKEN2
Checking this out right now.
It's 55 BPM, with droney synths, twinkly piano, and no drums. If you let it play a C chord for 3 minutes, it will work for rubato accompaniment, sounding kind of like Eno's
Music For Airports.
But if you actually put chords into it, you will hear the grid.