Or a cash transaction or service swap, for example. These are properly termed Cryptoeconomics precisely because there's no ledger. Blockchain, the brilliance, takes the choice of ledger out of the hands of the transacting parties alone, and centralizes the record of every transaction in the same ledger.
Through a mind-fuck word association game, the shadowy originators of Bitcoin have you guys talking in Doublespeak about a massively centralized public ledger, centralized at the data layer and merely distributed over an ad-hoc CDN, not decentralized at the data layer like Nostr, and 180 degrees from private / actual cryptoeconomics.
You can't solve the Generals problem without centralizing something. Blockchains don't solve it without doing so, they just chose to centralize the most dangerous part to actual free trade -- the ledger.