Many heirlooms go back centuries and pass down through generations even as those generations move jurisdictions.
The Nyan cat gif NFT was composed by the original meme creator. That gives it value.
What does it mean for a baseball to be autographed with Babe Ruth's signature? If it's authentic, it means a great deal. There's no court of law that is going to validate if a Babe Ruth baseball is authentic or not and whether that fact gives it value or not. That is going to be up to the market of appraisers.
The crypto part gives you a perfect chain of custody. I'm giving you a digital item, that is provably rare and verifiably linked to the original creator of the artwork.