As another user said, the NFT is the ticket. A ticket is basically a receipt when you think about it, which is why it makes sense as a use case. It shows that you have purchased a unique item (the seat) and grants you access to it.
The artist/venue could make a ticket independently and without NFTs. They would then have to make them in a way that couldn’t be forged, and would have to create a distribution system. None of that is simple for an independent artist/venue to implement. By using an NFT all of that is handled by the decentralized network.
Again, that was simply an example to help demonstrate how NFTs have more use cases than just a picture of a monkey
kurogane