With something like Ethereum, you can build refunds into your payment model as long as you and the merchant agree on a set of trusted 3rd parties who can handle

With something like Ethereum, you can build refunds into your payment model as long as you and the merchant agree on a set of trusted 3rd parties who can handle any disputes. You can choose different trusted mediators for each transaction and can decide the rules (ex: how many of them are needed to decide that a refund has to happen). You can also choose not to trust any 3rd party. If I'm buying an on-chain digital item, I probably don't need to support disputes, but if I'm buying something off-chain and don't trust the merchant, I might want that protection.