Okay, so there seems to be a local policy of "discussions" in commentary need to be sent to the "chat room" corner. Even if the discussion is spot on topic with the question and answers posted.
Why in the name of quaternions would that be?
All you've accomplished is to discourage me from contributing. I'm having a deep rethink.
Follow up to Peter K.'s answer:
"That's the way we have always done it." is among the weakest policy rationales you can have. I was truly expecting something more substantive, something I hadn't thought of, something that arose out of considered debate by knowledgeble parties.
Discussion in the comments can be classified in five broad categories:
1) Clarification of the issues
2) Contention about the issues
3) Tangential Topics
4) Unrelated Topics (Tangents on tangents)
5) "Meta" talk
For the first two, some of the third, and the last, the value of the discussion is greatly reduced when it is removed from its referential frame. Only the fourth doesn't suffer from that.
But they all suffer from a significant drop in likelihood of being read by shunting them off to a "chat room". Yeah, I don't do "chat rooms", nor will I follow conversations to a chat room. I am sure many others feel the same way.
So yeah, it is discouraging when you have put a lot of thought into something, taken the effort to express it into just the right words for your intended recipient, to have it whisked away to somewhere it will rarely be seen, out of context if it is.
(Likewise, it is discouraging when a newbie deletes a question and your carefully crafted answer along with it.)
In my opinion, and it is broader than just for StackExchange, you will find the most valuable, and sometimes most entertaining, information in the commentary. On news sites, I sometimes just skim over the articles and just read the commentary.
Does StackExchange consider the commmentary valuable? I think the fact that MathJax doesn't work in the chat room is a pretty good indicator that it doesn't. It's a matter of preference so I can't say you are wrong, but I can certainly say I disagree.
The discussion will often contain the key detail that an interested reader is missing for comprehension that does not get covered in the question or any of the answers.
The rationale implicit in your answer is "It makes pages too long and hard to follow." I don't find that a problem as I am used to scanning through documents, but I recognize that is not true for all. You asked for a suggestion, I have a simple one: Once comments reach a certain count, put all but the last few in a scroll box with a slider bar similar to the way long code inserts are handled. That shouldn't be too tough.
Olli, about MathJax working in the chat room.
Here is a screenshot excerpt:
Here is a zoom view:
BTW, I agree 100% with this comment.