What actually is a smart contract because I’m confused by it. Once I heard mark cuban talk about it. He said the contract settles when proof of work is completed but who decides when that is? If I have a smart contract for a new roof and we both put money into a smart contract that says the money will change hands at the completion of the project who decides when the job is done? There’s no downside to the contractor getting your funds tied up and then never doing the work. Sure you get your funds back but why should you ever have them tied up?