Note the qualifier "marketplace clears". In the process of clearing, a market undergoes price-discovery and any arbitrage opportunities are taken and thus removed.

"Marketplace clears" doesn't imply that everyone agrees that the price = the value. McDonald's has cheeseburgers on sale for ~$1. That's probably the market clearing price. I still don't think a cheeseburger creates $1 of value for me.

If Moldbug makes a basic econ error (by conflating value and price), then there's no reason to trust any other part of his "return to first principles of economics."

Fiat money is a good, in economic terms. It exchanges for other goods.

"exchanges for other goods" is a bizarre definition of good. The hoarding-of-physical-objects metaphor is misleading.