Permissionless has nothing to do with blockchain. As an example if you want to exchange currency without blockchain you can do that by buying gift cards and exc

Permissionless has nothing to do with blockchain. As an example if you want to exchange currency without blockchain you can do that by buying gift cards and exchanging them for cash on any number of online markets. Blockchain provides integrity guarantees given a number of malicious participants. That's all it provides over any other ACID database.