What's wrong with an attendance sheet?
Why does attendance matter?
Beyond that most of my anthropology classes (I minored in anthropology) had class discussion as part of the grade. I even had one professor who had us move the desks into a big circle as we entered (and put them back as we were leaving) in order to better facilitate discussion.
Also you'd have to be there to hand in previous assignments and get new assignments. Most of my classes (in all classes) had assignments due either every day or at least most days.
You'd also have to be there to hear about changes in the schedule. If you only show up for tests and the day of the test changes you'd need to know.
Plus pop quizzes. They aren't used much in college, but I think I had one or two.