I don't know if that's a good thing, or if it will ever happen. Take a look to England, even when they were in Euro, they did not adopt the coin, because the british pound was stronger and they would lose power if they did it. They are even getting out of European Union all together. Powerful countries don't want that to happen, so I don't think we will ever see a global currency that is backed by governments. We might have bitcoin being used all around the world, but that is different.