Actually, this is what I've been talking about forever...

Forget audio loops. You are a) at the mercy of whoever makes the loops in the first place - and whether they can decently record ALL the chord and inversion/root combinations you might ever need, and b) at the mercy of the hardware and whether it's latency is matched to the latency of the hardware sounds in the arranger. And forget about editing them, changing the sounds, changing the rhythm, changing the swing, etc.. What you get is ALL you get.

Anything that takes the MIDI end of things, with it's inherent ability to edit, change sounds, change anything you feel like, and apply more natural performance behavior, including, as seems to be mentioned here, the ability to add a hopefully MUSICAL degree of randomness or change to the pattern can only drive along the progress of the arranger as a viable accompaniment tool.

More natural guitar emulation is already a thing we all take for granted, nowadays (or hope makes it to OUR arranger!), more natural performance emulation of other instrument's particular 'flavor' and more musical chord changes, less jumpy jumpy, more smooth voice leading, and now this, the possible hint of a self generated quasi-random variation to the parts, and we start to see the possibility of auto accompaniment sounding less repetitive and plain 'auto' than it currently does.

To a certain degree, this already exists in software... BIAB, even when given exactly the same chords, will generate a MIDI file with subtle variations in it every time you ask. Something that does this in realtime does not sound like something that is too difficult to achieve...

But then again, what possible use could this be to a poor beach musician? Jimmy Buffett's music is ALL done with tiny, short, repetitive four bar loops that never vary