I also think it has the potential to become used worldwide by anyone. U.S. dollar intented to do so, but because of the fact it was associated with the United States, any opponent or unfriendly country would not use it. Bitcoin has the advantage to be totally neutral, hence it can perfectly become the prefered way to transfer money abroad.
I think
Bitcoin is already an international currency because the whole world already knows and uses
Bitcoin. Only, not all countries allow
Bitcoin and maybe we should use
Bitcoin clandestinely.
To me,
Bitcoin has become my first major job or investment tool. It can happen because
Bitcoin is the cheapest and easiest investment tool. I'm sure a lot of people are investing too. And also, in various places to shop or restaurant already use
Bitcoin for transactions, for example in my country.