All the examples you give are things that can be done (and are done in practice) without NFTs, and you don’t really explain why using NFTs would be better.

Stock ownership also gives you a payout. And yes you can use NFT’s for authorization, but you really don’t need to. That was already possible back in 2005 with some PHP. Although those systems were and still are often centralized and rely on the integrity of the infrastructure and the intentions of the people running it, you can’t host a service on the blockchain. Smart contracts can’t host a site. There still needs to be something in between the blockchain and the client.

I see the potential of a public ledger but most blockchain projects seem to simply use it as a marketing gimmick.

I guess if there is an issue with verifying authenticity of art and using NFTs solves that issue this makes sense. Selling digital art using NFTs is still dumb IMO, as there is no real concept of owning or displaying an “original digital painting” like you can do with normal paintings; in that case you only get a fairly abstract proof of ownership (NFT avatars on various sites and NFT items in games could change this if implemented widely I guess).

Other than a few similar use cases they still don’t seem very useful, and it I think in most cases they solve issues that already have good solutions.