The type I'm discussing, something like the Lightning Channel and Plasma operators, these are roles that have cryptoeconomic properties that don't allow them to take over your wallet or refuse your service.
edit: The base premise of having a smart-contract being itself the escrow is perfectly achievable. This doesn't mean that such a setup is the best solution to every use case and I believe that we'll see plenty of developments in this area in the coming years.
For now the best approaches use game theory and computer science to reduce the amount of "trust" the parties must have in each other and the system itself but they are very much under active research & development.
Are these guys really add more value to the economy than chargebacks? I very much doubt it.
Take for instance the role of Plasma operator or Lightning Channel operator; The role allows for a third party to have the costs of setting up infrastructure for you to use, but at no point are your funds held by the operator and you are always able to exit a contract if you submit on-chain evidence of fraud.
In plasma for instance, the operator and seller could collude against the buyer but any "illegal" operation they do on-chain is enough for anyone to trigger a mass-exit and cause financial and reputational loss to the operator.
A common theme in all the on-chain payment technologies I mentioned is that they do not put any one party in "charge" but the volunteers who run staking channels of any sort (plasma, lightning, etc) can and will suffer financial damages (loss of deposit, etc) if proven to act maliciously.