For me, bitcoin, although taxed and incorporated into federal monetary system, will still keep it's best property: The government cannot print more bitcoins.

So, while they still use dollars because of this perk, bitcoin will have a wider, more respected environment for growing.
When it takes over, govt will HAVE to balance it's budget, hold it's spending, or overtax people, which will bring up to sight the reality that increasing public spending eventually crashes the economy.