I actually think that deleting off topic would benefit the forum. Or at least not allowing the creation of low quality/"daily threads" such as "what is your favourite drink" or "when do you eat" because they are literally just used for people spamming posts. I saw someone with over 3k in Off topic (or something like that, can't remember) with super short posts and they're all low quality. I only see a legitimate thread like a few times every few days in there.
Besides, they probably just don't want spammers overall and not just in the campaign.