Bitcoin can also possibly replace the US dollar currency if ever we have the capacity to do huge contractual trading between governments and other trading companies or institutions.
I believe this also, because the US government is now planning to implement a cashless society. And I'm thinking that bitcoin is the currency that will replace their currency which is dollar. And because they can see the convenience of using it.
For sure people tend to agree with this kind of replacement one a law was created for the replacement of it.