I don't see it.
I began thinking like there's even one thing legitimate about them, but I honestly can't find any.
Forget about the digital artwork non-sense. People will lose interest in that sooner or later.
Imagine you guys are gamers. You play a blockchain-based game that supports NFTs where you create your own characters. Those characters need to be trained to acquire skills. Fighting skills, armory, speed, etc., etc. Let's compare this character evolution in the game to activity points on Bitcointalk. It takes time and hard work to build-up your account/character. With traditional games, you never become the real owner of that character you spent time creating. You can't transfer them between games. If your hard drive fails, your data is lost, and your game progress and characters are lost as well. When the game developer released a 2nd edition of the game, you have to start from 0 again. But if you could make it your own NFT, it's yours. Now imagine if you could import/export these characters and use them in different games. There is your use case, and that creates a market and demand. I am not a gamer, it doesn't affect me personally, but I understand how this would appeal to those who are.
You see one of the biggest problems with your arguments (and a lot of others like it) is that you always say what you can do not why you should do it this way. It is like saying "If you want to travel to another city, you can walk thousands of kilometres." And you wouldn't be wrong, you can walk to another city, that is what people did hundreds of years ago (or used camel!) but it doesn't mean you should do it this way.
I'm not really a gamer either but I've played some games back in my days. There was a game called Dragon Age where you could create your own character and save it both on your disk and later on EA servers or when it came to Steam you could save it in your Steam account. Then after they released Dragon Age 2 you could import that character (from your disk or your cloud) into that and follow the story that way since all your decisions in 1.0 affected some of the story in 2.0.
You owned that character since you had paid for it and you could transfer it to another game.
No NFT needed.
Now lets compare bitcoin.
With traditional currency (fiat) you have to use a third party to transfer it, specially large amounts and long distances. There is no other option but using a third party when sending money over the internet. That third party has been a nuisance for many reasons from security, trust issues and fraud to reversibility, high cost and slow speed.
When bitcoin came, it addressed these problems and solved them. Now you don't need a third party to send/receive money, it is very secure, it can not be reversed (after proper number of confirmation), it is cheap and fast, protects your privacy and a lot more.
The point is that bitcoin did address an existing problem and did actually solve it. Bitcoin is not just another way of doing things in a poorer way, it is actually an alternative way of doing things in a
better way.
My point is that you can't say the same thing for NFTs or tokens in general.