Eventually they will make all your money digital. They will track everything you buy.
Then at the very least they will sell your information to advertisers, and at worst retain totalitarian control over all your purchasing power.
Its already happening in China - the state has the power to prevent people from travelling etc. based on their "social credit"
The US is making a CBDC (central bank digital currency). No matter how pure the intentions of creating a government backed digital currency are, it will degenerate into a means of control
Which is why Bitcoin starts out doing exactly that by default?
Trustless decentralized architecture makes the Bitcoin network incredibly robust against attacks on its principles. It can't be changed (without users/capital switching over to new version), stopped or censored by anyone.
All you'd need is a small private army, a few lawyers, an historically accepted jurisdiction, and you'd be ready to go with your central ledger.
I don't think you're right to say double spending is the only thing being solved with proof of work, I think people are trying very very very hard not to centralize (for no good reason in my opinion), despite the prohibitive cost, and why ? Because of that insane fear the ledgers would be changed: hence you'd have to admit the author was a bit right that eventually this whole story is to protect paranoid people against a very absurd risk at the cost of asking government to subsidize reopening coal mines...