I've seen dozens of articles on NFTs, and not comprehended a single one. So when someone made an NFT of the first Twitter posting, I didn't understand how that would be a means to generate any sort of financial return. Even if the copyright on the posting was sold, it was too short to copyright, and the news articles about the NFT quoted the post. This is even more true for today's article about NFTs corresponding to Leonardo da Vinci and Van Gogh paintings, which are entirely public domain. (Unless there's some scheme afoot to retroactively lock up all of humanity's heritage.. hope not..)
The inference I'm guessing at is that NFT is something like Bitcoin, only the proof of work is in trying to round up the author or present owner of some obscure work and getting them to sign a piece of paper? But how is that even scarce? If tomorrow I said that I'm issuing Non Comprehensible Tokens and start mailing out unique digital codes for each species or exoplanet or chapter of the Bible, would I be making money the exact same way? Do the NFTs even have a value, or are they just a written excuse for wealthy people to hand each other money for reasons only they understand?
Interim comment: I've seen a huge response and many thought-provoking ideas, but I still don't think we've reached the full answer. To me the most striking observation so far was Kevin's comparison to an artwork consisting of a (replaceable) banana taped to a wall. I think Jamesqf's answer of conspicuous consumption may be the start of something. And Damian Yerrick's description of other rights bundled with an NFT may give a good hint. David Jacobsen runs with that a little by pointing out the NFT issuers aren't nobodies (though they also certainly aren't da Vinci and Van Gogh). I'll add my suspicion that comparisons involving the "Million Dollar Homepage" or naming rights could be fertile. This may be a means of buying publicity, some of which is preloaded in the abundant news coverage; I don't know if there are other terms to the NFT sales to ensure that purchasers will be prominently credited in museums. The field still seems open for someone to give a new and more persuasive answer.