Every adult should have an identification card issued by a government agency, whether it is a state or federal card. A photo id does make it easier for authorities to identify individuals when determining minor traffic violations, crimes and witnesses at the scene. ID cards with security measures on them should be the norm in a developed country to avoid illegal immigrants as well.
Identification cards are for people to be able to prove their identity to authorities, they have no other purpose. What other purpose could they have? If they were not required for such a function, no one would even have them. A driver's license is even designed for such a purpose. It is the whole point of ID cards.