Quite simply, escrow. Programming complex escrow, that holds and releases funds when appropriate conditions are met. People have bundled many escrow statements

Quite simply, escrow. Programming complex escrow, that holds and releases funds when appropriate conditions are met. People have bundled many escrow statements together to create entire banks. People can pool different currencies together to create liquidity pools and exchanges between currencies. It's not all that different from (transfer)wise except a bit less owned by one central firm. It can be "pay this vendor when this thing ships" or "pay out this pot when this event or game score happens." Any measurable metric online can turn into the IF of an if then statement.