I believe in the long run virtual currencies while be a staple in global transactions. I also think they will hold value sort of like precious metals against the continued devaluation of fiat currencies.
In the long run you have to increase the money supply, barring some large reduction in growth/population - which also means a deflationary turn (which is a huge blow too) - while virtual currencies are locked into a limited supply. There is a finite amount of BTC that will be available.