I'm unclear on why everyone seems to think that Bitcoin reduces governmental power. It makes all transactions public -- no more cash deals, hard-to-subpoena international wire transfers, etc. It makes the job of law enforcement much easier.
You could argue that the increase in law enforcement power would offset the decrease in power from not being able to issue fiat currency, but that would mostly be a silly line of argument to pursue.
Force mostly has to be individually applied, and you can only take it so far before you have massive pushback in the form of civil unrest.
Printing money, to pick a simple example, is much more effective and can be done across the economy as a whole.
Could you imagine police forces breaking into everyone's home and taking half their cash in a matter of days? It's unthinkable that that would happen for logistical reasons alone.
But that's what we've effectively seen some modern western governments do just recently by rapidly deflating their currencies.
Abolishing fiat currency would take away that power, and make no mistake it is an immense power. It's the power to shape entire economies at the stroke of a pen.
Why would law enforcement be eager to support a technology which...
Also, if they can freeze (stall) certain wallets indefinitely, that's pretty much as good as asset seizure.
Others getting 'pissed'? What are they going to do? The very limited consequences of Snowden-leaks pretty much show that they can do such things and ignore protests, if the government leaders are okay with that.
It makes the job of law enforcement _different_. Their existing skills/procedures/relationships/precedents for dealing with cash and banking-industry-mediated finances don't work for Bitcoin - presumably that makes it scary for any change-averse members of the LEO community.
This gives them an off-switch for The Terrorists. And, side effect, a way to blockade groups they don't like.
A registry may happen because businesses have an incentive to have creditworthy customers. Sometimes you want to prove you have collateral, that you have cash flow, that you've paid people in the past. Bitcoin does that nicely.
So, you've got your public wallet to prove you have money available, for making credit decisions, for deciding whether to sell you a house, etc. And your private wallet because "fuck the police". There's not even a good way to know if a wallet is located in the US or somewhere else.
And, if there are people willing to take coins from people's private wallets, there will likely be a solid economy outside the government's control; as there already is; there's a massive barter and cash economy. Bitcoin makes it slightly technically challenging (like, how do you get and spend bitcoins to and from your private wallet if you can't accept your paycheck there and can't order goods shipped to your house with it).