Earlier quoted context omitted.
It's best to think of NFTs as deeds to the art (or certificate of authenticity), rather than the art itself. I wrote this a little while back, and it might help you. https://interjectedfuture.com/nfts-unbundle-ownership-from-e... If NFTs as deed to art isn't convincing for you, check out ENS. https://ens.domains/ It's a name registrar that's a smart contract. Each ENS domain name is an NFT.
May be a dumb question but how can we certify that the same asset doesn’t exist as two or more NFTs on different block chains. There are tons of them and each can have its own monalisa.
You can't. But surely some wise guy is pitching a blockchain for that right now.
It's actually worse, the same certificate could exist on multiple blockchains, and none of them guarantee approval by the original artist; all could be legally void certificates of nothing.