[masterbit]

Blockchain coordinates databases over different legal entities. That's the magic. It's still your DB in your Datacenter when you run your own node. You have autonomy over your own records with your keys. And you have visibility of all other records. A big central DB is under the control of a central body. With a blockchain the central control is / could be limited.

[bitreality]

Definitely, but this is a feature that a centralized authority like the fed would prefer to do without. Whatever technology is behind any sort of "FedCoin" would certainly not be blockchain. They will not relinquish control of their currency, doing so would make themselves obsolete.