a) You have the physical card. It is in your possession, and the only way for you to lose it is for something physical to happen to it.
b) You can look at and enjoy the card in its physicality. You can show it to others, and the only reason that is the case is that it is physically in your possession.
Contrast that with NFTs, where all you "own" is the idea of owning a thing. If the thing your particular NFT says you own is a digital image, anyone can still see that image, and it can be deleted from the internet without your permission or any warning. You lose the exclusivity that's the main draw of owning something rare and special, and you don't have any practical control over the thing either.
They're not worthless, they're worth less. I could easily hang up a counterfeit Mona Lisa on my wall and get a kick out of it. And if I stop getting a kick out of it, I can put it on Craigslist for $100 afterwards.
Of course, there's absolutely no history behind the painting as it wasn't painted by the renaissance man. No one would pay to see it because it would be about as significant as a JPEG of the Mona Lisa. However, that doesn't mean that it's worthless. Even that JPEG can make for a good phone wallpaper.
Ownership is based on the ability to have something tangible of a limited supply, but as I established before, digital assets can be freely copied. What are you trying to do? Artificially limiting this? Trying to push through a completely new idea of 'ownership'?
The only thing owning an NFT gives you is bragging rights of a perceived ownership. But if I say "I don't recognize this NFT proving anything", copy your asset, reproduce it and sell it somehow, you can't stop me. You claim to own some bits and claim to be able to prove that, but I can just ignore that completely, since there is zero legal grounds for this.
This is why it is absolutely moronic in my mind to have an 'ownership' idea on digital assets. It's already bad enough in online games to have in-game assets, which is in a walled-garden, under control of the company making the game, so yeah, there they can do this, it adds some perceived value. But to actively introduce this concept in an open digital world sounds absolutely crazy, counter-productive and conceptually against everything my ideal version of the internet would be: open and free as in beer.
It turns out that when you take stupid and scale it up massively, it becomes even more stupid.