An NFT can represent any digital asset. Digital assets are a key part of any "metaverse".
If NFTs become the standard then you could theoretically take your assets off Facebook into another Metaverse without losing your items. NFTs help avoid lock-in and put pressure on Facebook to play nicely with others.
I am shocked how this stuff hasn't made its way into HN yet. Everyone PLEASE DYOR and start by researching Cryptopunks and Bored Ape Yacht Club, you can spread out your NFT horizons from there.