You're right, this isn't a Wiimote killer. The Sony Move is an attempt at a Wiimote killer. This is more like the Wiimote + Balance Board (which I own).
Having used the Balance Board, it's got major limitations. There are games which want to you "jump" on the Wii (Snowboarding), but if you actually jump, the game freezes and displays a warning: Do not jump on the balance board. Major gameplay killer.
Kinect sees your entire body and can handle jumping, moving, and more, without a controller. Start a game by moving your hand over the on-screen button. This will be awesome for casual and party gaming, since nobody's controller will be out of batteries.
This isn't a Wiimote killer, it's a game-changer. Microsoft has a hit with this one. Until Sony's mind-reading controller comes out, that is...