I'm not here to argue with anyone, but I like the idea of this case, and think it is very Apple like. I don't keep a case on my phone because it is awkward, but let me explain my reasoning. This is a design that solves a few problems, and avoids a couple that a battery case creates normally. iPhones are slippery? Here's a silicone case to steady that grip. iPhone battery isn't lasting long enough, here is 5 more hours. Added benefit of better cell reception? Awesome.
Plus now you can keep the case on with all your accessories with the integrated lightning connector. And something I don't see anyone mentioning completely indeed has to do with the bulk of it. Normal battery cases cause a lot of bulk and since a lot of using the phone has you holding it in landscape, these thin edges make for almost a game controller type grip. Instead of that awkward fat battery case feel. I think Apple took its time designing this, like all of its products, to try and see what benefits they could add without making anything worse. And I think they did quite well. Sure there are cheaper options, but that's not even an argument worth stating with Apple products any more. We get it.
Just my two cents. Sure, I can see Steve rejecting this sort of thing, but he's not here to ask and great businesses have to evolve. They are trying out something different for a case, not reinventing the wheel. Simmer down folks.