Earlier quoted context omitted.
Russia also have very good digital services. Now in one go government can send you conscription notification and immediately block your from leaving country as well as revoke driver license, block your banks and even phone numbers. Also since all the data available about you in one place any malicious actor who can bribe someone with access can immediately get all your data: passport info and tax id, addresses, work…
The judicial system is the one who is supposed to prevent abuses of power like this. What you are proposing is essentially security through obscurity, if the data is fragmented all over the place on different institutions it is really hard to be exploited in the government, but still totally can be. Confidential data can have better security checks and encryption layers so it is accessible only by the citizen itself…
It's a great way to combat bureacracies. It only doesn't work against smart people, such as computer hackers.