To keep bad drivers off the road? To suspend privileges when you kill someone with your car?
Social security numbers were originally created for linking people to their social security accounts but has now become our national ID because there is an inherit need for one in the modern world. The problem with SSNs is that they were never designed for their current use-case.
> And why should a country/state know your bank account number(s)?
A state will always have access to and the capability of seizing your account funds. This is a necessity for a multitude of reasons that I can list out, but I'll let you use your imagination.
Take a look around the world. Take a look at history. Autocrats don't need an efficient ID system to take control of their citizens. People willingly give up their freedoms and align themselves with autocrats when they use the same propaganda and fear-mongering tactics that have been used for centuries. It has nothing to do with the government amassing a database of their population. Once the autocrats are in control, they will create whatever system they require.
The only way to avoid tyranny is to fight for liberal values at the ballot box. Anything else is bullshit. Your guns won't do shit when your local militia is aligned with the autocrat in control.