Why you can't just screenshot an NFT

NFT is new and confusing, I hope you can elaborate more on the possible usage of it as a smart contract, certificate, ID or w/e other usage it has than just a jpeg.
Also on the possible privacy issues of of a hot or cold wallet, and how the public can see the transaction history.

My understanding of it is surface level, and as far as I can tell, it can be used as admission tickets, certification of ownership/legitimacy, and as a recipe or ledger.
A lot of nft/crypto bros are imaging it being able to apply to medical, real estate, limited addition or brand name items, but I wonder how much of it is applicable due to specialized fields needing a certain amount of procedure and authorizations.

There's also layer 2 or something, where the gas price, or fees of transaction is reduced to cents instead of the current hundreds or thousands.

Gamestop is schedule to released its own nft marketplace that may present a new usage for NFT that may be redundant or revolutionary. It's something to look at it when it comes out.