I had the 6/6S Apple battery case and then 7 Apple battery case, after trying Mophie cases, and the Apple cases were miles better in terms of day-to-day use (completely transparent to the user) and size. I was completely fine with hump. But because I can charge without problem throughout the day (now wireless), I won't get this (even if it worked with an iPhone X) because the added weight outweighed the few times I actually needed the extra capacity. I'd rather just carry a small battery pack with a built in Lightning connector for those few times it really matters. $129 is too much for something I might only need a few dozen times. Plus, if you put your phone in your pocket, the silicon coating started wearing almost instantly. Didn't affect function, but looked terrible. If Apple made these so that you knew you could use them for a few generations of phone, and the materials were more durable, I'd consider it. The convenience was great.
I'd be interested in seeing the bottom/bottom inside of the case. I'm assuming that there a Lightening plug on the inside to line up with the port on the phone, and a Lightening port in the battery portion of the case, which is a great way of getting rid of the chin. It would also make this case much more efficient than the Morphie case, which charges the phone wirelessly (which doesn't make any sense to me given the loss of efficiency).