It manifests God's love. God's love created us free, not robots, and our free choice of evil is the only thing that makes hell. Freedom, once again. Decline infinite love and you experience infinite lovelessness. If we refuse, it remains unfilled infinitely.
All sin is a little souvenir from hell.
It is crazy. But it's real. Love stoops to conquer. If you don't like goodness, you wouldn't like heaven. Their seeds are.