The government is not in a hurry to take bitcoin, because it has an unstable price and everyone is afraid that at any moment the bubble may burst. It is more effectively considered as an additional opportunity for earning.
It is not just about the unstable price or the volatility of bitcoin but rather it is about the control. Bitcoin is decentralized and is also something new and using it possibly has some huge consequences. The governments would rather conduct some study first before they would accept such kind of currency. If the government find some merits on it they will make some move to place it on their system and so a good example is Japan.