Bitcoin will be treated as another currency like USD but it cannot completely replace the USD because without interaction with the government it is not possible. As of now, bitcoin has changed many aspects in the fields of economy and it makes the government think about it. But we have to wait and see in coming days how the bitcoin will be treated as.
i think bitcoin will remain as number one currency of the world, as there is no such other currency which we can compete with bitcoin, and that is the reason that we are expecting that bitcoin will remain as number one currency of the world for ever.