[Oxidation]

Presumably the equivalent to the Brazilian notary blockchain would be a centralised entity (in this case, probably Growth Tech[1], or perhaps the central government or a key sharing scheme between the both of them), since that's a private permissioned blockchain.

[1]: https://growthtech.com.br

[latchkey]

IMHO, the whole private permission based blockchain thing is just a poor attempt at a very slow database. This concept really hasn't caught on, primarily because of the centralized aspects.

While we are very far way from this concept in the real world, I'd prefer my proof of identity documents to live on something that isn't controlled by any single entity other than myself. Sure makes them a lot more difficult to revoke or modify without my consent.

[Oxidation]

Even with a hypothetical maximally decentralised system, there's always a centralised chokepoint where a specific organisation (including and perhaps especially, a state) that you wish to prove your identity to chooses to unconditionally accept records from the system.

[latchkey]

How is this any different than people choosing to accept (or not) payment in bitcoin?

[Oxidation]

Well, exactly.

But I would still say that in your original example, the use of blockchain is particularly unnecessary.

[latchkey]

Well... there is a distinction there... permissioned blockchain, no... "decentralized" bc, yes. All assuming that governments agree to acknowledge it, which, I agree, will likely never happen on a global scale. That said, other globally disruptive things have happened, like shorttermrentals and rideshare... so, who knows.

Imagine 1000 years from now and people are on mars... you think that everyone is going to be carrying around a paper passport book? It is going to look vastly different than it does today. I personally feel that it is important that the technology for things like this are experimented with now.