I had Splashtop running on my Asus tablet paired with a 360 controller. It ran Skyrim at about 30FPS but with a hell of a lag. It whet my appetite for something more like this.
At home, I have my gaming PC in one room, and TVs in several rooms. With this, I can take the machine into any of the rooms and continue playing in more comfortable surroundings. This could even trump/replace the steambox. Why have a dedicated, less powerful machine in the living room when you can take this little machine anywhere and stream where you like?
I know once you move out of the home LAN, lag would be an issue, but I guess there's nothing technically stopping you from trying out on the move or in the office, or tethered to a mobile device. It may just be a bit shit, but still would be interesting. I may be wrong there, I know nothing about networks.
Nvidia are in a really interesting position. I doubt they're expecting to sell the number that a traditional console would sell, but then they're not trying to push any proprietary formats with it, like vita or 3ds carts. Android, steam, emulators - already exist and will continue to do so.
But yeah, this has got a jaded gamer super excited - I even think the thing looks good. I've often looked at a controller and thought why doesn't someone just go all out and put triggers and handles on a portable. I hope the screen is as good as the Vita's.
Also, downsampling would be nice.