Fact is, if I had "invested" in 100 BTC only 5 months ago when it was hovering around USD$10, that would have cost me about $1000. And now it would be worth $10000. There are not that many investments that have that kind of return in such a short time. You'd have to be dumb to believe that people aren't doing exactly this. You don't see 1000% returns and just ignore it and wonder about its utility. Right now, it's a volatile and risky currency exchange being intentionally used to ride the rising popularity into a cash la-la land.

At some point people are going to convert this toy back to a real-world currency and take their winnings home with them. I don't know what's going to happen then, but I don't believe it will be good. Perhaps 'stabilizing' would be a good optimistic name for it.