In high schools and colleges around the country, there are thousands of debating teams that debate a single proposition many times each year. During the course of a year, individual teams make the case for and against the same proposition. It is a good discipline to have to make a public argument that one does not necessarily agree with. It forces one to look honestly at the same issue from different perspectives. Unfortunately, very much like attorneys, in the heat of competition, debaters quickly begin to worry less about the truth of the debating topic and more about winning.
Truth is only incidental.
Debates build good rhetorical and reasoning skills, but they habituate debaters to focus on the structure of the argument and not on the truth. The judges are to rely only on common knowledge and not bring additional information to bear on their deliberations. Outside formal debates, in argumentation, we are generally honestly trying to persuade others of the ideas we believe in. Although sometimes competitive spirits are aroused and reasoning disappears, real persuasion is the goal. In causal discussions and arguments with friends and colleagues, there are no dispassionate judges that decide purely based on the evidence presented.