yep this a good open question. The bitcoin guys will say, in parts of the world economies where bitcoins are taken for both input costs and for selling prices,

yep this a good open question. The bitcoin guys will say, in parts of the world economies where bitcoins are taken for both input costs and for selling prices, then exchange rates are irrelevant because bitcoins are used in all transactions, so there are is no forex volatility. Of course we are far away from that sort of adoption. The more persuasive argument is that people are worried that sovereign currencies will themselves become too volatile for real economic transactions if debt problems grow too much, debasement by central banks cause inflation, etc. In this sense, bitcoin is a great hedge against world uncertainty, and will do very well if problems with the euro mount, USD debt skyrockets, etc. For the same reasons people care about gold when people lose faith in fait currencies, there is a good chance people will care about bitcoin if things go crazy.