Answer:
To get the other person's point of view.
Step-by-step explanation:
In the counterclaim, you explain how the other side of the argument is good, also explaining how even that can be bad.
For example:
Opposing side: "Homework should not be banned"
Your counterclaim: "Even though teachers can see where students are in class, it causes stress."
You explain the downside of the opposing opinion.