I think it’s already irrelevant: cryptographic proofs of video evidence is difficult to communicate to audiences while watermarks will be learned by AI as trusted and injected into AI videos anyway. Also, in between the lens and your eyeball is usually a pipeline of editing applied anyway so either the cryptographic signature ends up with every layer signing the modifications applied + the previous layer or you stack watermarks. But ultimately the original problem is how to communicate the cryptographic chain validity.
Most users don't care, but in theory a newspaper could use this tech to verify certain camera images and their readers could just trust that they've vetted things.
In practice, ordinary users don't care much about mainstream media anymore.
In theory this is where zero-knowledge proofs can come in. That would allow you to apply transforms to the video (crop, contrast, resize etc) and be able to prove the exact transform that was applied. However it's still computationally expensive.
