In the early years, homework is only for the sake of getting kids in the habit of sitting down to do work everyday. Unfortunately, some kids realize that there really is no other reason for it and don't bother wasting their time, only for the sake of their grades. They get in the habit of not doing homework even when it is useful; they don't make time.
I wouldn't say ban it completely, but only assign work with a point. Points are few and far between in elementary and middle school, but maybe the educators will start educating children instead of just getting them into "good habits."