To any given government, Bitcoin looks like just another foreign currency. In many foreign countries, you can get dollar denominated bank accounts. How is Bitcoin any different than this status quo?
The reserve bank of Bitcoin is completely immune to coercion, you can't freeze funds, you can't stop transactions, you can't do anything at all to the funds in one of those accounts without the consent of the account holder. If the account holder doesn't want you to, you can't even know who they are. Altogether, the entire system is the exact opposite of the global banking system, it is extremely poorly understood and almost entirely uncontrolled.
And that's just with the bank analogies, if you take it up a notch and compare fiat issuance to bitcoin issuance it gets even more frightening from their perspective. There's no nation they can apply diplomatic pressure to to change the fiscal policy of Bitcoin, that fiscal policy is linked to interests utterly alien to their own, even.
From their perspective it is indeed a dangerous thing, the only question to my mind is A) How long will it take them to figure this out and B) when they do figure it out, what kinds of actions will they take to try to destroy it.