Metadata isn’t part of the core spec, so NFTs don’t have to link to anything. You can only verify ownership of the NFT id. What the NFT represents is up to the

Metadata isn’t part of the core spec, so NFTs don’t have to link to anything. You can only verify ownership of the NFT id. What the NFT represents is up to the author. It could be a credential to a web application. It could be a pass to a venue checked at the door. It could be anything to gate access by asserting if the wallet holder has a specific id or balance greater than zero of said NFT. An NFT is a unique token. What builders do with it is up to them. Mostly it’s been art. What else could builders do when they have a permissionless way to assert that a user owns a unique digital id (NFT). It’s worth exploring more.