Unfortunately, that doesn't mean that it'll actually be accepted everywhere, just that it has the potential to be accepted everywhere. Hopefully, it'll become more popular as people see these sorts of benefits.
This is only one approach to defining a global currency
I mean whether a currency is used like the US dollar to be considered as a global currency (since that's what you seem to imply). Obviously, apart from the US dollar itself, there are no more currencies used as widely and wildly. On the other hand, the US dollar is not used everywhere either, and if we consider only the territory across which a currency is accepted (as a metric for determining its global character), then only the US and Bitcoin together would cut it as truly global currencies. Even Euro is rather limited to circulation between the countries of the Eurozone itself, or the countries which avoid the US dollar for various reasons (such as Iran, for example)