I don't find any logic in this argument at all. A signature spammer cannot increase their post count or get paid by making low-quality posts anywhere in the forum because signature campaigns have managers who are checking posts manually, posts in any signature campaign aren't counted by bots that look only at the post count from the day previous week ended and the post count when the new week ends.

So, saying that a thread should be moved to off-topic only for the sake of signature spammers not being able to increase their post count doesn't make any sense to me. A bad poster will be a bad poster no matter where their posts are. We can't move every single thread to off-topic so that signature spammers who are posting in those threads have their posts not counted. I believe signature campaign managers have that covered already, and they don't pay or count posts with no substantial quality.