I'm against it (except in the Sales forum) for three reasons:
First, in a debate, the thread starter could close the topic to avoid being proved wrong.
Second, why should a thread close just because YOU'VE finished with it? What if it's moved on to another area that is of no interest to you, but is of great interest to others?
Third, it increases the chances of duplicate threads. "I wanted to ask a question about something in an old thread, but as it was locked I had to start this one."