Actually assessing students could mean, you know, testing them orally instead of handing them assignments. Or at least letting them have a written exam in front of you.
Assignments can be useful for learning, as a way to keep students on-track. In my undergraduate days, assignments were optional, and scores on them were ignored if the exam had a higher score. That struck me as a good approach, but nowadays I think it would lead professors to create easy final exams, to avoid the low scores that lead to student complaints and problems at tenure time.