Countries can just use a database and do the same stuff as crypto incredibly efficiently by comparison

I just don't know how it works in detail on the bacnking side as i havenot worked with it.

My thought was that a crypto based system could replace perhaps a sea of different approaches and alignment efforts across banking systems and if a central bank/banks are just need to approve a block, instead of mining it, the basic idea of a transparent cryptosigned blockchain might be useful.

But yes i don't think they need something like this as the current system seems to be very trustworthy. I have never heard of a bank creating money out of thin air.