At some junction in this chain (as far as I know as an NFT skeptic, to put it mildly), you (want to) pay for ownership of something non-fungible, be it meatspace or digital. So sure, that thing at the IPFS URI might never change, but I can still copy it, or it might not have originated there, or it's some representation of a real world item, where the representation of course can be reproduced.
You've added another layer of immutability, but I have yet to see where that's relevant to anyone who understands what they would be buying, as there are always more layers.