Repetition helps with memorization and practice. For instance, languages would be nearly impossible to learn without homework because languages must be constantly practiced in order to maintain. Other skills, like math, require practice with different problem sets to ensure students understand the concepts outside of a controlled environment. So long as the amount of work is not unreasonable, homework should not be banned. Students need homework to practice the skills they learn in class, and they should be able to consult with a teacher on what they learned or struggled with.
Many classes are not ones where repetition is a useful skill, and homework in those cases should be adjusted accordingly or eliminated.