on this line of discussion yeah, this thread will get locked eventually and a v4 made. off the top of my head:
1. One of the reasons a lot of mods became frustrated with the Ban thread was that there would be too much side discussion/chatter on a regular/hourly even minute by minute basis. Also people asked a lot of indirect questions unrelated to immediate bans/deletions. It became very difficult to find anything in there. So having this thread provides a runoff trench so the other thread can be more focused and useful.
2. It's nice to have a place for general questions. Where people can ask whatever they want even if they're not in any trouble or haven't been banned or had a thread messed with. The other thread needs to be focused so users can get specific answers to immediate issues regarding mod action. This thread helps facilitate that by giving people a place to ask general stuff.
3. It's actually not a bad thing that any discussion thread has wander room. I do think it's important to bring a discussion back to the topic if it wanders too far or for too long. But even as a moderator, it's always been my observation that things work best when discussions are allowed to evolve and occasionally even wander as long as they are topical in nature rather than what has been defined as a directionless chat back-and-forth ("hi" "hi" "what you doin?" "bored" etc)
4. It's good to have an established place where moderators aren't in that sort of what are primarily often confrontational exchanges. Not always, but generally in the ban thread, it's about users being angry about bans or thread actions. And it's good that there is a place for people to directly confront moderators about that stuff. But it's also good to have a place where mods can talk and answer questions without having the situation being confrontational.
5. (mmmm five)
Most of these points kind of intersect but you get the general idea.