Probably it will not be a legit currency until whole the world accept it. Bitcoin is decentralized and this is also one of the reasons why it cant be legit in this circumstances. But we just dont know what will happen in future, everything is changing.
I think this is because most people thinks that bitcoin is an investment rather than a currency. Being a currency is quite hard because it needs to be accepted in the whole world, otherwise it will be impossible. This goal of bitcoin will take a long time before happening