I don't understand why NFTs aren't used as event tickets, it's really convenient
Perhaps it does not actually offer an advantage when they are compared to a centralized system of tickets which are already being used today. The only different thing we all would see with NFT as tickets would be those already used ones becoming collectibles in a decentralized Blockchain, like Ethereum, for example... so we would be talking about the same issue which led most of the NTFs to their downfall, their especulative nature.
This technology has actual use cases in the the world, when comes to proving ownership in a decentralized way, that is for sure, but people already see very convenient to rely their ownership on centralized registers and the laws of their countries, instead a Blockchain.
Perhaps instead of writing a post you could have done a Google search instead. There are many ticketing providers on several altcoin chains that use NFT technology, and these ticketing companies offer countless advantages over traditional centralized systems. A further Google search could have yielded in information how the current ticketing systems are pretty much scams and hurt both event hosts and visitors.