A signed print of a picasso painting would quite likely go for quite a bit, even if you could get the same print sans signature for $20 in the gift shop. Even one created post-death by family foundation etc as a limited edition probably would. Some people do value the scarcity and it being tied to the creator more, think an NFT represents that and thus pay more money. (I personally am not interested in owning NFTs, but "people spend money on scarce things I wouldn't spend money on" isn't exactly a new phenomenon)