> well, some NFTs do have thousands copies, etc. — they're not always unique

What? No. They are unique and not the same as the others, that's what makes them NFTs in the first place.

A NFT that has thousands of copies is just a cryptocurrency... You might mean that there are "collections" of NFTs, where the artwork happens to be the same and the author is the same. But each individual piece of that is it's own NFT and not a copy.

You're just being extremely pedantic around the use of the word "copy" to try to make your point. If you have thousands of things where the artwork is the same and the author is the same, we have a word for that: "copies".

Putting an ID on each one doesn't make them any less "copies"; they're just numbered copies. Sure, you can call that a "collection" if you want, but they are a bunch of instances of the "same thing".

Well, without being pedantic about the use of "copy", we might as well use "NFT" and "cryptocurrency" interchangeably, but it's useful to make the distinction between as they are different.

If you pipe /dev/random to 100 different files and hash them, the content are "the same" in the sense that they are all filled with garbage. But if you hashed the content, you'll get different hashes. Use those as Global IDs, and you have something like a NFT. The same, but also not the same as they are unique.