I don't know why but for me it is totally normal to carry my ID and drivers license in my wallet everywhere and I'm fairly sure most of my family and friends do the same, but it might be a remnant of communist times or something. What I find really weird is that in Denmark they expect you to carry your yellow card (technically and ID with your personal number) even though its useless as it does not have a photo so you might as well give the number from your mind, they can only check if the name is correct.