The government is smarter these days. I'm pretty sure they could figure what to do for bitcoin. And just probably, they may consider using bitcoin too. ITs always good to listen to what they say, like if you can't beat them, join them.
When bitcoin is used widely, the market capitalization is larger, say 1 trillion dollars, the price will be more stable than now. The governments will treat it as currency, and tax accordingly.
It is very risky for a government to use bitcoin, because the price of bitcoin is changing and the losses can be in millions or trillions of dollars, so it can be banned in some countries.
The government do not have to use the bitcoin. As long long as it allows its citizen to use bitcoin, we are happy.