The problem I see is that even though Bitcoins are extremely popular, there simply will never be enough of them for this ever to become a true currency, or to be used in any major way for currency exchange. So in order for a crypto currency to actually be used in a major way in the world economy there has to be a coin which has far, far more quantity.

In order for that to occur, the crypto currencies have to evlove, which occurs in the form of alt-coins. Eventually there will be a coin that truly does have the quantities to become a real currency for actual trade between nations, with enough volume to handle the multi-billion dollar exchanges that happen.

So, for now we have our current crop of alt-coins, and they are evolving, which is exciting, and I do in fact forsee a time when we have people using a common crypto currency instead of a fiat currency.

Unfortunately I think we'll see the fiat currencies fail before that really occurs, or maybe that will be what will make it a reality. But we'll need something besides Bitcoins to handle it.

Can you imagine if some future form of Bitcoin becomes the world trade currency instead of the US Dollar?