NFTs are being used to store smart contracts and authentication for digital artwork and other digital assets.  A record is created on the blockchain that records a transaction associated with meta-data.  Meta-data is usually going to be a URL that links to a digital asset, say a digital picture or a digital video. So, when an NFT gets put onto the blockchain, it records the terms and authentication of the transaction related to that digital image. It's like a digital signature.  Like an artist who signs a painting.  That signed painting is going to be worth a lot more than a print copy or an unsigned version of that painting. just like in the real world, the signature of the creator creates scarcity. The scarcity that's driving market prices into the thousands, tens of thousands, hundreds of thousands, and millions of dollars for a single NFT auction.