I'd use it as a permanent camera affixed to my head. Basically I'd record every day of my life, since my memory is terrible, so I'd just rely on that. I suppose it'd be really helpful to preemptively organize and make notes for every video on what I did so I could easily search through it if I ever needed to recall something in detail.
Although in reality, I wouldn't pay that much for it. And I personally don't like Google and the Internet's snooping as it is, so there's the whole privacy angle to it too.
I would only have wanted an invite if they gave me one for free to test it out or something. I wouldn't want an invite to buy it early, especially when I'm positive that if it does well, there'll be a better version in three years tops for half the price. Maybe another company will release their own version with better stuff... Hey, there is Baidu eye already in the works:
As for revolutionary, I suspect it might do well if the price goes down. I remember when the iphone was announced that there was a decent amount of skepticism on the net in regards to its success, and well, look how it's doing now. Who knows?