Unlike central banks, a miner with >50% hash-rate can't "print money" as it wishes, that's still regulated by the algorithm.

http://bitcoin.stackexchange.com/questions/658/what-can-an-a...

The bond market is a pretty strong check on government-backed currencies. It's a stretch to say that a central bank can just print money as it wishes.

Wait, why can't that miner simply unilaterally switch to a better algorithm? Especially if the switchover isn't drastic, the ledger could be effectively destroyed before the minority notices in time to do a clean fork.

For the fork to mean anything other clients have to also switch algorithms (or they won't even accept any of the fork blocks as valid).

The central bank can shut its systems off for a day without worrying about all its assets disappearing when they come back online.

Better, what's the difference in someone holding a massive amount of compute at their beckoning and using it in a similar way? The answer is, there is no difference. Power is power.