I agree that most built in styles are mechanical, repetitive, bland. Nevertheless, there are styles in there that are really intricate.
pair them with good Kontakt libraries and you’d swear you heard a real band.
As everyone seems to agree on: midi ain’t dead at all.
Being really into ECM style jazz, Dejohnette, Joshua Redman, Joey Calderazzo, I came up with my own styles. Took me a long, long time to master stylemaking, but I am really proud of them. And enjoy playing with biab more, now. Even putting up with all the weirdness and bugs of it. :)