There is a possibility that when Bitcoin is used on a large scale, with at least 80% of people using Bitcoin for shopping and expenses, the government may change its mind about Bitcoin and issue a Bitcoin banking license, which we will never know when it will come, and most likely will never be legal. So far, Bitcoin is still an experiment, not 100% successful, and it will take time to see how Bitcoin will develop in the end.
Even if so, at the end of the day, they still can't control Bitcoin at all. Look how Bitcoin works, you can use it anywhere you are as long as you have an internet connection. That's how Bitcoin is, decentralization.
To be honest, I am not sure if that Bitcoin banking license will work because one of the many uses of Bitcoin is to eliminate banks which we can have our own bank from our pocket, and that's Bitcoin do.