I disagree. It's off-topic so I'm not going start an endless discussion about intrinsic value.
> Decentralisation can quickly become federation. Example: a global id system where the "miners" are countries. It removes the need of physical passports and their associated costs and delays.
As long as humans submit the external data to the blockchain someone can cheat with the data. Actually, cheating is a nice feature if you need double passports for diplomats, spies or informants. The result is a blockchain with permanent records with data you can not fully trust because the data did not exist on the blockchain in the first place.
I'm all for a digital solution instead of physical passports but I do believe this can be solved with distributed systems and international standards, instead of permanent records on a decentralized blockchain.