I don't think we can say that it won't work for some things. This is all about new experiences, taking games forward. The controller expansion allows for any number of new methods of interacting. When we don't know anything about the games or the other expansions there is no way we can say it "can't" do anything. All we know is that it can do a hell of a lot of stuff no other input device can do. The demos looks strong and the sensitivity and design is well thought out.
This controller is, to put it simply, revolutionary. It is beyond exciting. It's leaps and bounds above anything I expected and so well thought out. It makes Sony and Microsoft look boring.
To the person who asked "can we use the Gamecube controller for Revolution games" the answer would be no. There's no way they could make a game to take full advantage of that controller and then go back to the old way of controlling. And I don't understand why anyone would want to, it's like playing a Gamecube game on a SNES pad.