It's not at all there is rampant fraud in the NFT market. So much so Deviantart made some detection software to help alert artists their work is being stolen.
All that can be definitively proved outside of other methods is who created the token.
It sounds like you're talking about cases where, as I said, there's "earlier evidence of somebody else being the creator of the work". Intheabsenceofthat, I think the token would be a decent piece of evidence in favour of the token owner.
So would posting it anywhere online essentially. Twitter would work for the same usecase. Or the old sending it to yourself through the mail thing.
NFTs also don’t put the image on chain usually instead just linking from the metadata so a fraudster could register a bunch of placeholder NFTs and then later put stolen art where the link points to. Hey Presto you can steal art and “prove” the actual creator is the fraud.
Well, posting the actual content publicly would obviously make it public, which registering a hash on the blockchain would not. "Sending it to yourself through the mail" would probably be the competition, and I would say a cryptographic hash is at least as good as a postmark, as well as cheaper.
Anyway. I wasn't talking about NFTs as they exist today. I'm just saying the original concept (as I understood it) seemed basically reasonable, before everybody went insane.
All that can be definitively proved outside of other methods is who created the token.