Restriction and prohibition is the main weapon of any government. Bitcoin can not circumvent that, in everything else the coin is still unregulated because it is a decentralized asset
The real question is why any government needs a weapon against its own citizens.
I think you have to open your eyes and think broadly about of your question because the answer that you were looking is in front of your eyes. A little common sense and it will sink everything into your brain.
The government can do/make any regulations regarding of the needs and security of their people. And if Bitcoin will become a threat to them due to its decentralized attribute they may follow the steps of other countries for banning Bitcoin and cryptocurrency.
No, they won't fight Bitcoin and cryptocurrency when it becomes a threat. They will fight it when it becomes personally beneficial for them to do so (regardless of it being a threat or not). That's the problem.