> - is it a good idea to tie various public records together under a unique ID
Generally, yes. It simplifies dealing with government bureaucracy. Proving your identity is generally something you will have to do anyway, this is will just remove a bunch of hoops you have to go through.
> - is it a good idea to issue voluntary ID for those situations where people need to prove it
One of the countries I lived in had a system similar to this one. It worked fine
- typically you only needed this ID when opening a bank account or registered for work. Originally it was a tax registration ID (which is why it was related to banking and working), but it was secure enough that it was later repurposed as the actual unique ID. Nowadays I think they issue one to every registered person (e.g. newborns).
> - where is this going to be made mandatory and under what circumstances will it be used against people?
We are talking about the government here, who has the monopoly of force. If you live in an authoritarian country where the government fucks over citizens, they will do it to you irrespective of you having a mandatory ID or not.
My actual main concern is the level of access private corporations have to the records tied to this unique ID. I am highly suspicious of corporations (e.g.: banks, healthcare providers, etc).