Unlike the Typo keyboard, which communicated with the iPhone over Bluetooth and extended the length of the device to unwieldy proportions, Samsung's keyboard case snaps on top of the phone's display, effectively blocking half of the screen. The phone recognizes the keyboard and adjusts its user interface accordingly, shrinking everything to the top half of the screen. Keypresses are sensed by the screen underneath, eliminating the need for any batteries or Bluetooth pairing hassles in the keyboard itself. You can pop the keyboard on and off pretty easily, and if you want the full glory of an unobstructed display, you can snap it to the backside of the phone for storage.
Samsung couldn't tell me when the keyboard case would be available or how much it would cost, but I expect it will hit shelves around the same time as the Note 5 and the S6 Edge+. And can you really put a price on tactile keys?