You definitely aren't wrong, Croccydile. Tech demos are cool, but it's up to developers to come up with creative and compelling ways to use these tools. Engineers are there to just give you the tech, but they aren't game designers or artists. That's why I didn't think anything of Natal until Peter Molyneux came out and introduced us to Milo:
http://www.videosift.com/video/E3-2009-Project-Natal-Lionhead-Milo-Project
While I agree that this is still a tech demo, it's at least an original glimpse into what is possible with it.

Surely we won't see how well this will do until real developers get their hands on it, but personally I'd love to see what could be done with it when given to the brilliant creators of, say, Katamari, Flower, Eden, Boom Blox, etc. There will be a lot of crap, as there is on the Wii, but it might be worth sifting through it to get to the truly unique interactive bits of genius.

As far as the consumer goes, I don't think the price of entry on this is going to be much more than a normal controller. Since it uses the already available Playstation Eye. It should be very accessable, which may give it an edge when convincing developers to create for it.

Did you see the Sony conference, and their motion control prototype?

http://www.videosift.com/video/E3-2009-Playstation-Motion-Control-Prototype

They felt the same way about the need to have a controller in your hand. I dig it.

I pretty much wrote Natal off until they showed what Lionhead had done with it.

http://www.videosift.com/video/E3-2009-Project-Natal-Lionhead-Milo-Project