I agree most contracts benefit from "wiggle room", however you can build wiggle room into blockchain-enforced smart contracts (e.x. by giving n-of-m arbiters/courts ability to override the outcome), but you can't build absolutely enforced "code as law" on existing legal systems.
I don't claim to know how useful this will actually be, but it seems like a potentially interesting new capability.
There's not many use cases where a purely technical solution has meaningful impact on the world, though. The "code-as-law" will generally have to be supported by "law-as-law" at some point, and that can be overturned arbitrarily.
What good is having technical ownership of some private key if your government declares you have to give it over or face jail?
For suitably powerful privacy coins, the government shouldn't be able to tell if you used your private key or not. So you claim you lost your private key and spend away. Of course, there has to be an off-ramp into the real world at some point, so all this actually gets you is access to the black market. Opinions may vary on how useful that is, and how much blockchain can succeed if it insists on fighting regulation tooth-and-claw.
Claiming you lost your key is called contempt in court. Judges generally don't take kindly to that tactic. A lot of people some how think they can "hack" the legal system...it generally doesn't work out so well for them.
I don't claim to know how useful this will actually be, but it seems like a potentially interesting new capability.