> This is also a national security risk. A nation state interested in war will have an easier time shutting down a small handful of things simultaneously to quickly cripple our economy.

If you take a broader view, you will note that the United States telling Visa and Mastercard to shut down all service in <country> will cripple that country's financial system.

The dangers of someone bringing your economy to a halt by 'hacking our systems' is overblown. These kinds of problems can be fixed, or routed around in a few days.

You don't have this option when the systems you rely on are completely controlled by another nation state.