NFTs are actually different from and separate from bitcoin and cryptocurrencies. It's true that you can buy NFTs with cryptocurrency, but you can also buy them with dollars or Euros or gold or anything else.
An NFT is a non-fungible token that can really take any form. Non-fungible meaning that they're unique and cannot be substituted or duplicated at all (because they are encrypted by way of blockchain). Currencies like USD and bitcoin are very much fungible meaning that you can substitute one of the same kind for another. For example, I can take a US dollar and exchange or replace it for another US dollar and have no change in value or any other material difference.
One of the best examples of NFTs is how lately trading cards (and other artwork) have been sold as tokens. In this example you have a "digital" trading card or piece of art which also has a digital token that's encrypted using blockchain certifying that it's unique, and that you own it. What's making these things sell for literally tens of millions is that these tokens are unique and cannot be copied or counterfeited due to the blockchain encryption. Super rich people are basically paying millions just to say they have a unique string of 1s and 0s stored on a computer somewhere that 1) they cannot see, and 2) has no functional use. This is why it's being treated as a bubble about to burst.
Honestly NFTs are one of the dumbest things ever conceptualized unless you are an investor taking advantage of the perceived value to make some money in the short term.
The whole idea is ridiculous. Let's say I post to my twitter account (I don't), and let's say one of my tweets became popular. At that point I decide I'm going to "sell" my tweet to someone so they could say they own that tweet because it was such a good one. Keep in mind there's no physical tweet, or anything tangible whatsoever. It's just the mental concept of ownership. So I put the idea out there that, "Hey folks, you could be the EXCLUSIVE owner of my really funny tweet, and I'll even create an encrypted digital 'token' that proves you own my tweet." All it takes is a few rich assholes in an auction pissing match who want to prove that they're richer and more exclusive than everyone else and all of a sudden someone spent $10M for a "token" stored on a computer somewhere that they can never even see, nor can they do anything with it other than sell it to some other idiot later. But...they now "own" fryowa's tweet. It's theirs.
They cannot see it, it has no functional use, there's no royalties, future income generation, and it's totally illiquid, but they just paid $10M for an encrypted certificate that says they own it. A tweet.
This is EXACTLY what Garza's doing with his trading card. Is he smart for doing it? Yep.
Is someone smart to buy it? NOPE. It's a fad and a bubble (at least in the way we're discussing it here; I believe there will be a market for NFTs representing tangible assets in the future), and even if you look at it as an investment, who the hell is going to give you a dime for it 5 years from now? If Frank Kaminsky had done this 6 years ago and you paid say $100,000 for one of these digital token playing cards, do you think you'd find anyone to give you five grand for it today?
NFTs for intellectual property, especially digital property with no physical form, is a completely stupid concept, again, unless you can make some cash quick from resale. It is nothing more than a pissing contest between wealthy folks to buy electrical charges stored on a computer with zero use or income generating potential.