Think of a booth at Comic Con, where an artist hands out signed copies of their comic books. The comic book itself is nothing special, but the signature is. But there is a problem: if you ever want to sell the signed comic book, how do you prove it's a real signature? NFTs solve that problem.
But even in offline space, the artist or seller could transfer an NFT to your account. You could then verify its authenticity (or even before the transfer).
Anyone could verify it's authenticity using even Adobe Acrobat Reader, which has had this functionality for decades.
An example of something is the fact that I am a vim donor and a neovim initial backer. I really like that I’m in backers.md. If they would have handed out NFTs for backing, I would have loved that too.
None of this needs a energy-hungry blockchain.
This is just a mechanism that provides that in a general way.
It’s sort of like, how, before Uber you could call up the few cabbies you had who you liked and get a ride but having Uber was a game changer anyway because the friction fell below some threshold.
They do leave a public audit trail in the blockchain/ledger, so potential buyers can know how many authorized copies of the asset there are (at least on a given NFT platform). That is generally an improvement over baseball cards (which may not have accurate manufacturer-supplied print counts).
Personally, the only value NFTs currently provide in addition to say PGP/GPG digital signatures are features similar to joining a country club. When you buy the right NFT, you can opt to schmooze with other owners of that class of asset (celebrities, sports stars, etc). I suspect governance or additional smart contract features will provide more benefits in the future, but they may also come with SEC/CFTC oversight so they may also come with more drawbacks.