It seems that the only thing you own when you purchase an NFT is the NFT itself. Not a little jpeg that it points to; just the bit of code on the blockchain.
It's kind of tautologically stupid. You buy a receipt that states you own that very receipt.
But if people buy deeds instead of the house itself (i.e. most NFTs) then the link becomes broken and the signifier of “ownership” is less useful.
The deed is only a signifier of ownership, nothing more. If you can prove in court that the possession of the deed itself was improperly transferred, the state will return the deed to the rightful owner. Or annul the old deed and create a new one. (At least in the US.)
As you say, a deed is not a bearer instrument but the concept of home ownership which it symbolizes has legal protection.
And as it is used for digital goods, the signifier of “ownership” is already broken, as multiple people can have a copy of the item without their being any ownership conflict, unlike a house.