No they aren't used for tests or attendance. You could totally function going to school without your ID on you and not get in trouble if you don't have it, you just might not get access to all the equipment and resources the school offers

I understand how it sounds like a police state thing but it has been a thing even when it was laminated paper. It is also only tied to the school and shows only a pic, name , student ID number and then obviously whatever school it is because they all have unique designs and layouts.

Also it's super fun if you hanged onto them every year!