Charge your iPhone and battery case simultaneously for increased talk time up to 25 hours, Internet use up to 18 hours on LTE, and even longer audio and video playback.* With the Smart Battery Case on, the intelligent battery status is displayed on the iPhone Lock screen and in Notification Center, so you know exactly how much charge you have left.
These improvements come at a pretty high cost, however: they make your phone look like a completely ugly piece of crap that was designed by a crazy person.
The Verge’s hypothesis on this ridiculously horrible design is that it was done to avoid infringing on the patents held by Mophie, a company that makes iPhone battery cases that avoid looking like someone just duct taped a 4-pack of AA Energizers to the back of your phone, which makes perfect sense.
Personally, though, I’m going to believe that a few members of Apple’s design team have a bet going to see if even hideous monstrosities will sell well exclusively because they have an Apple logo on the back of them… It just makes me feel better about this for some reason.