I'm still struggling to understand it. The blockchain in this case _doesn't_ provide a single source of truth. As you yourself said, it can be invalidated or a legal system can override it. So I can't just "check the blockchain" and know the actual ownership. So aren't we just back to where we were but with an extra step of enriching some miners/stakers?
What we're moving around on the blockchain, _fundamentally_ is liability. The blockchain is an accurate register of who's holding precisely which bag if something goes wrong. When money changes hands and the NFT moves, the risks move around - a new person is being protected, the new owner of the NFT.
There's a lot more to transacting property than title - condition of the place, planning permission, 50 other factors. All of that is being represented as claims, and liability if those claims are inaccurate.
