Alfie Kohn lists the effects of giving homework to students who do not understand. It will make him feel stupid. She may reinforce incorrect steps. He might conceal a lack of understanding by relying on friends. It teaches that that subject is beyond understanding (The Homework Myth, p.113).
"At the same time, other students in the same class already have the skill down cold, so further practice for them is a waste of time... Thus, the nearly universal tendency to give the same assignment to everyone in the class, while understandable in light of time constraints, is awfully hard to defend pedagogically" (The Homework Myth, p.113).
What good is homework to the student with perfect understanding? How does homework help the student with no understanding? It's cruel and unusual punishment for both. The next day, they'll have a topic for conversation: School sucks.