I hardly ever use them. Touted as being the best thing since sliced bread, you very soon came across all the issues that have been mentioned above, and I found another. One of my exam students was working out a very complex arrangement for her Grade 7 exam. We needed to change styles part way through the tune and that would have involved seamlessly switching from a regular style to an audio style. Of course you can't do that, as the audio style has to load in. You ended up with a gap in the drum part. Useless. We had to use regular styles throughout.
With the advent of Revo drums (and to be honest it's not before time as VST drums have been using round robin samples [wave cycling if you wish] for years), they were no longer needed. I think Yamaha saw audio styles as a stop gap until Revo drums were ready.
As for the other parts of a style being audio, I'm not convinced. BIAB does it with ease, of course, as you've told it exactly what chords, fills, breaks etc you want in advance and it calculates what it's going to do before starting playback. I've created some great sound tracks with it. But when I tried the Ketron Audya, I had problems getting it to change chords predictably and smoothly. And when I started asking it for things like Fm11 or D7b9#5, it couldn't deliver. That was a few years ago and I haven't tried one since, maybe they've got things to work better. If full audio styles had been a runner, then Yamaha (and, as has been said, they did the legwork on it and got the patents) would have surely run with it.
Conspicuous by their absence on Genos and SX series keyboards, I think Yamaha have consigned them to the bin. Good riddance to them IMHO.