> A blockchain is the logical extreme of where you end up when you think about how to sync backups
It's not. Blockchains are only eventually consistent among nodes. They're designed for synced backups among adversarial peers.
There's no reason for a government agency to use one internally. There are better ways to sync backups when the people with access to make updates are also authorized to do so.
Internally, you don't need it, agreed. But that is centralization risk exemplified in this incident. Which isn't necessary. Every notary could be a node. It would be a lot more resilient, and it would look a lot like a blockchain (not necessarily with a crypto currency though) if you do it properly.