Here are some kinds of debates:
Arguing with parents: This usually occurs in a house or in a car. These debates help to decide where a family will go on vacation, whether an allowance will be raised, and other similar decisions. These debates often get no where and waste peoples time. However, these can help make better decisions when everyone cooperates. These debates aren't structured well, so family members usually end up shouting at each other.
Political campaign: This occurs in a rented auditorium. These debates usually are held to show citizens what viewpoint different candidates have. These usually don't help people to arrive at a better decision, because the candidates generally already have a viewpoint which their party supports, and it probably won't change during the debate. This form of debate is structured. Candidates are given time intervals to talk. This helps to get the politicians' viewpoints across in the time given.
Court cases: This happens in court houses. These debates usually serve the role of determining whether someone is guilty or not. They definitely help to come to better decisions, because the final verdict is the sentence of whoever is on trial. These debates are structured, and this helps to come to a decision in a timely matter.