It’s a battery case, but it’s also a concession. In releasing its first Smart Battery Case, Apple is essentially saying battery life on the iPhone 6s could be better. It’s also saying a lot more.
If you took Apple’s silicone case and slapped a battery on it — then covered that in silicone — you’d have this case, more or less.
Because it has that battery pack, which needs to be charged just like your phone, the bottom of this case also sticks out. Apple has cutouts below to redirect the sound coming from the speaker forward, which is the same 90 degree turn the mic hole takes.