I predict that we will have some kind of Blockchain based Crypto currency for every country in the real world, very soon. We do not have to incorporate this into virtual worlds, for this to be a reality, because we can implement this in the real world. There are currently several countries that are moving towards a cashless society and Crypto currency is just one of the technologies that can help them to achieve this goal.

I doubt that Bitcoin would become a global reserve currency, because the world are simply to divided to accept one currency.