>But how can you prove that you've paid an artist for a specific piece of work?
Again, another author talking about NFTs who doesn't understand what an NFT signifies. An NFT does not confer ownership of the underlying work it just confers ownership of the NFT itself, unless you ALSO agree to a secondary contract in the process of buying the NFT. Which, at that point, you've just negated the supposed value of owning the NFT in the first place.