> Most NFTs contain a content-address (hash) that is pointing to data on IPFS.

Is there a stat somewhere showing that IPFS is the most common kind of URL in NFTs?

> Maybe marginally better than URL but not very much IMO.

Vastly better than a URL. Content-addresses points to content that can be served from anywhere. URLs point to actual locations. Anyone can seed the content behind the IPFS hash, including the owner of the NFT.

While with a URL, you cannot change it. If the owner wants to make it work after it disappeared, they would have to buy the domain name, make the hosting work again and then setup a server there, add the file so it can be served.

While with a IPFS hash, the owner could just turn on their IPFS node and everything works as before.

Big difference.

A URL has another huge disadvantage: a URL is the address of a thing, not the thing it is pointing to in itself. The thing it is pointing to can change. If you paid $70 million for a URL pointing to a Beeple artwork, you might be upset if the owner of the URL changed the content to a Rick Astley video.

Can't it be a URL with an IPFS address in it? Or should it be s/URL/URI? Does it matter?

But this has nothing to do with the NFT.

But it does matter and has to do with the NFT. If you put a URL, whose content can change over time, the NFT that effectively be changed. At least what it's pointing to.

If you're using a content-address hash, you can be sure that you can always get back the same result from that hash as when you got the NFT N years ago.

Yes, I can see that, but seems completely unrelated to the NFT. The NFT and the content it points to are independent from one another.

If the buyer takes down their pin, and nobody else has it pinned, then that's their prerogative. The NFT is still there on the ledger, unless the whole blockchain goes down too.