Technology

Ok I think I need to reframe what authority means here. An authority is a government or an organization or individual that a government authorizes to act on its behalf. It is the decision maker when it comes time to physically remove a claimant from the premises.

A blockchain is a leger, a document. What you're proposing sounds to me like legally defining it as the final say in ownership. To do that is more or less a complete rewrite of property laws in a way that would have far reaching effects, especially on marriage, government enforcement, and lending. On lending this would basically eliminate the capacity to use your house as collateral without a full conditional sale, and in that case I really hope you trust your banking institution. For government enforcement, this would eliminate leins as a means of compelling payment of owed money, which means other methods would be required (this is especially an issue in contexts like child support, where debtors can be particularly hostile). And for marriage this will really screw with inheritance and divorce proceedings. The fact that you can't cash out and sell the house asap when your partner requests a divorce is something I personally think is good.

Additionally, in every democratic nation to my knowledge, the existing registry of land is public. Public of course when referring to ownership by the collective of citizens, something the blockchain is less so. But it's also publicly visible, just like the blockchain, except instead of having to download it you go to the appropriate store of public records and request to see it or to obtain a copy. At the very least in my country there's a ton of information you can get in such places for asking. Property transfers, court records (unless a judge has sealed them, usually because sensitive information is contained within), building and digging permits, birth and death certificates… Most people only get what's relevant to their life, but some people (like investigative journalists) have to look through public records for a living. Could it be valuable to digitize it all and upload it? Yes but not without risks, which also apply to blockchain here.

So yeah. This leads into a famous question: What is Property? And ultimately that's a fairly deep rabbit hole, of its own. So what is ownership? The ability to direct the state to utilize its monopoly on the legitimate use of violence in defense of your right to control something. No ledger can confer that. A state can declare a ledger the ultimate record of ownership, but it can just as easily take it away.