Yes, a smart contract is not a legally-binding agreement, although it could be a component of a legally-binding agreement. That’s my point.

The smart contract in my hypothetical scenario might be something like a transaction with 3 parties: you (the customer), the construction company, and a third-party verification service, that executes your payment to the construction company when any 2 of the parties agree to execute. This theoretically prevents the possibility of any 1 party defecting and running away with a monetary benefit (including the third party verification service, which couldn’t run away with the cash like a traditional escrow service hypothetically could).

But my point is that even in this case, if the construction company and third-party verification service colluded to run away with the money without completing the work, you would still sue one or both of them, and my prediction is that the courts would treat this essentially identically to a scenario using traditional contracts.

But for this arrangement to work the customer, the construction party and the third-party need to enter into an agreement, i.e. a traditional contract. A traditional contract is legally binding, so of course the courts would treat it as legally binding. The smart contract may be part of the agreement but a smart contract by itself is not an agreement and something cannot be a legally-binding agreement if it isn't an agreement to begin with.

I suspect a court would tend to take the existence of the smart contract as a pretty clear indication of the intent of the involved parties. But of course if you’re entering a significant commercial agreement like this you had better make an explicit traditional contract as well.