I think this is pretty accurate:
Former Federal Reserve Chairman Alan Greenspan said Bitcoin prices are unsustainably high after surging 89-fold in a year and that the virtual money isn’t currency. “It’s a bubble,” Greenspan, 87, said today in a Bloomberg Television interview from Washington. “It has to have intrinsic value. You have to really stretch your imagination to infer what the intrinsic value of Bitcoin is. I haven’t been able to do it. Maybe somebody else can.”The worst part about it is that computers are just burning up electricity doing useless calculations to mine Bitcoins. You may as well get them for collecting your own shit. People are stupid.