Now suppose each of use are selling the 'first' post of that data. How does a buyer know that we're really the first?
And so I'm saying that even claiming 'first' is practically impossible via blockchain. Even if someone knew about both of the instances above and could arbitrate between them, there might be a third, older instance yet.
1. For example, say they sell to one of the big companies and the new boss with an MBA in gamer milking decides that virtual land needs annual property taxes, utilities, and improvements purchased from the company store or it’ll be reclaimed or simply that they’re creating new, more desirable terrain which will devalue yours. They control the code and servers, so your options are paying, giving up, or trying to convince other players to build, operate, and adopt a clone. The blockchain’s heavy cost doesn’t appear to be providing anything significant.
The only thing I can think is proof of authorship, but private key cryptograph already solves that.
Edit: after reading some other replies I've come to the conclusion that NFTs provide a way to prove who put a file on the blockchain first. Thus the use case is trustless transfer of the ownership of this fact of "being first", which is where the scarcity of the NFT comes from and thus the value.