Where this breaks down though is that contributory infringement is a still a thing if you offer a service aids in copyright infringement and you don't do "enough" to stop it.

Ie, it would all be on the end user for folks that self host or rent hardware and run an LLM or Gen Art AI model themselves. But folks that offer a consumer level end to end service like ChatGPT or MidJourney could be on the hook.

And it isn't just businesses who carry this risk. If a business was depending on a large inflow to make payroll, and that inflow gets reversed, the people who are expecting payment for their labor also are subject to a payment reversal.

There's definitely a lot of benefits to reversibility, but it has very real costs and tradeoffs.

What this ruling does mean though is that the government can't prosecute a US person for using TC.

Well, in many places, traditional copper pots is dying faster then the fax machines people still want to use. Fax over VoIP can work, but it makes for a lot of headaches if it doesn't.

That's where zero knowledge proofs come in. If you know the root hash at state a, and the new root hash at state b is given along with a zk proof, that proof data can quickly prove that the state change from a to b was arrived at correctly. In this case, the benefit of doing this on ethereum (or other evm l1 blockchain) is that those proofs can be validated on chain.