I agree its pretty basic but I think its more aimed at beginners to get them into playing ( and it helps sell pianos, I've seen that first hand )
I use it with my FP90 for some Rhythm Backing and although you can't do any editing of the Styles there is enough there to cover the basics. I could actually do a nice restaurant gig with this setup and not be missing much.
I was going to contact Roland and see if they're planning an update on it.
I was about to buy a BK7M but decided the app on my IPad was good enoungh. If I want more my BK9 is sitting close by.
Bill in SC --- Roland BK9 (2) Roland PK5 Pedals, Roland FP90, Roland CM30s, JBL Eon Ones (2) , EV mics, Apple iPad (2) Behringer DJ mixer