A game controller/protective case (so it doesn't have to fit around your existing casing). 2 shoulder buttons, analog stick w/ cover (for when it's in your pocket), and a few face buttons.
Apple's the first party and the one to set the standard. Money..
That just seems like easy money for them and they are the ones in the best position to do it. If you're into gaming and want something a little more hardcore or deeper than this would be fantastic.