Yeah, interesting that this notion of ownership is separate from IP. And, of course anyone can download the file itself.

So, they're essentially selling the right to declare you own it and the ability to sell that right to someone else.

tho, the important piece is the network. the network doesn't know or care if random people have a locally downloaded copy of the art. all sites, services, validations, virtual worlds, whatever on the network will hit the ethereum contract which gives up an address which you've proved you own by key signature.

the network can't see nor does it care about your local files.

which means, basically, any other appearance of the art in any other place is just an ad for the current owner of the nft.