National ID cards are generally associated with either: a) Enabling every company or organisation to learn everything about you. e.g. a bank can know about you

National ID cards are generally associated with either: a) Enabling every company or organisation to learn everything about you. e.g. a bank can know about your health care or education because the one ID you gave them for your financial services actually unlocks access to all others. This is why discrete identifiers for each service is preferred, despite the hassle or redundancy. or b) If carrying the ID on you becomes mandatory, it becomes a reason to needlessly arrest young people who have committed no real crime (because no one carries a passport sized ID with them everywhere they go)