An NFT is a way to attribute authorship in a mathematically guaranteed way.
If Taylor Swift signs ownership of a picture of her, you can know it is what she presents as real. If Elon musk signs a YouTube video of him offering crypto doubling giveaways, you can know he intended to represent the message as real. If the New York Times publishes an article signed with their key you can know it is meant to be published by the New York Times.
1) That's just using normal public/private key cryptography to sign messages, there's no need to bring in cryptocurrencies or NFTs
2) Public/private key cryptography would give us a way to verify that a message (or picture or whatever) from Taylor Swift is signed with Swift's private key, but it wouldn't help at all with e.g telling me that I'm responding to a real message and not a bot right now. Not to mention that it wouldn't even help much against deep fakes, since if I publish what I claim to be a secret recording of Swift, there would be no reason to expect her to have signed it with his private key.
Those two are the hallmarks of most of these "legit use cases for cryptocurrencies/NFTs" suggestions I've heard from cryptobros by the way: they're always some combination of "old technology that has nothing to do with cryptocurrencies" and "doesn't actually solve the problem".
If Taylor Swift signs ownership of a picture of her, you can know it is what she presents as real. If Elon musk signs a YouTube video of him offering crypto doubling giveaways, you can know he intended to represent the message as real. If the New York Times publishes an article signed with their key you can know it is meant to be published by the New York Times.