Centralized intermediaries are only trustworthy as long as they’re incentivized to be truthful. If another party comes along and offers them a bag of cash, the

Centralized intermediaries are only trustworthy as long as they’re incentivized to be truthful. If another party comes along and offers them a bag of cash, the intermediary might choose to betray its clients’ trust. Decentralized miners, on the other hand, are highly incentived to tell the truth, because it’s the only way they can collect fees. You’re right that you have to pay for the truth either way; the difference is that the decentralized approach gives you stronger guarantees.