Decentralisation allows trust-less assurance that money is sent, it's just that's not useful because the goods or services for which the money is transferred still need either trust or a centralised system that can undo the transaction because fraud happened.
That's where smart contracts come in, which I also think are a terrible idea, but do at least deserve a "you tried!" badge, because they're as dumb as saying "I will write bug-free code" rather than as dumb as "let's build a Dyson swarm to mine exactly the same amount of cryptocurrency as we would have if we did nothing".