we may or may not but I don't think this is reflective of it. This is just the fragility of digital societies were one hack or outage can kill entire national payment systems. A few decades ago any store could run three days without power or telecoms.

Here in Germany foreigners often scoff about how prevalent cash is, but to this day nobody has yet invented a payment technology that works without electricity, without transaction costs, and without a third party. As far as I'm concerned cash is still the most futuristic technology we ever invented

The “no transaction cost” claim is doing a lot of heavy lifting here. Cash may feel free to the person handing over a coin, but only because the costs are hidden upstream. Someone has to produce those notes and coins, swap out designs to keep ahead of counterfeiters, move them around in armored vans, count and recount them in tills, reconcile them at the bank, and insure against theft along the way. None of that is costless.

In fact, many retailers will tell you that cash is more expensive to handle than card, because every deposit requires staff time and often explicit bank fees. Society also pays indirectly through tax evasion and black-market activity, which cash enables far more easily than digital systems.

You’re right that cash is robust in a blackout, and there’s something elegant about a technology that works offline, peer-to-peer, and without needing servers to stay up. But the idea that it has no transaction costs is not realistic.

The US experiences these situations regularly due to its somewhat unique exposure to a dizzying array of severe natural disasters.

Having survived an above average number of these in my life myself where basic services were down for many days, I have a pretty good idea of what happens. Having cash versus digital doesn’t matter. No one is keeping track, people just take care of people. Everyone writes it off, moves on, and the community becomes stronger.

This is pretty wired into the culture. No one will accept your money in these scenarios even if you have it.

Precious metals fill all of your requirements. They do have other challenges, some shared with FIAT, some unique, but we've had the "technology" to solve this problem for thousands of years.