It has a magnetic hinge and corners which toggle the device's sleep state. The same magnets appear to hold it together into a triangle shape to act as a stand in two directions. To get that to work so nicely, you really do need to design the tablet and the case to work together.
Furthermore, you just know that Apple looked at all the accessories they stock in their stores and thought "Wow, lots of people are buying covers. We should clearly profit from those and prevent people having to suffer with shoddy accessory manufacturer crap."
I mean, yeah, it's still just a freaking cover. But distortion field aside, it's a quite innovative cover.
Reality Distortion Field Enabled.
http://www.blogcdn.com/www.engadget.com/media/2011/03/201103...