The point of it is that you can freely trade the NFT with others, letting you exchange the ownership of digital goods and thus letting you decide to give up access to whatever it’s related to in exchange for money and letting someone else get access to it. The NFT isn’t the digital good, it’s the proof of ownership of the digital good and I think that’s the bit that’s unclear to most. That proof of ownership is only good to then interact with whoever is the “gatekeeper” to access said good.

Just like having a contract saying that you have a safety deposit box at your bank still implies that you have to go to the bank to have access to the goods that are inside, having an NFT (the ownership contract) is only useful if you can use it to access the digital good it’s related to. If the bank burns down your contract is worthless, if the provider of the digital good the NFT is related to closes its doors the NFT is worthless.

The NFT = an image thing just made things super confusing because anyone can analyze the NFT to say “based on the specs mentioned in the NFT and the analysis of the original database, here’s the image” and anyone can spoof that to generate the same image on unofficial websites (but not in the official one which would check that the NFT is attached to the original contract), but when you understand that the NFT is just the proof of ownership it makes more sense.

It’s still decentralized because ownership and transfers are managed on the blockchain.