In both cases comments were removed to chat, by the moderator that provided the answer, in doing so removing the comments from immediate view, and providing a use-by-date before the chat will be marked inactive. The chat is only visible to people who click on the chat link, and while reading the chats the original question/answer is not visible.
This is my understanding of the use and value of comments: comments underneath an answer or question are immediately visible for any person looking up the question/answer, and provide context. A good comment is relevant to the contents of the question or answer. When clarifications are asked or faults pointed out, the reaction can either be added in the answer when the poster reckons it adds to the value of the question/answer to everyone, or otherwise in a comment. A set of comments, good or bad, form a frame of reference of the different viewpoints of the public using the forum.
On the other hand, long and prolonged discussions between two or three parties are often boring for the rest of us, and take away from the value of the post. So there are pros and cons to a long set of comments, that is understood.
The issue here though is a potential conflict of interest. Only moderators can remove comments from everyone from posts, the rest of us need to live with them, whether valuable or not. Moderators could potentially leave a flawed answer, and remove criticising comments from them. Please note that I say potentially.
We have more than one moderator, although sometimes it does not seem that way. Would a possible solution be for another moderator to judge whether a multitude of comments on the post of a moderator should be hidden from immediate reference in a chat room?
There have been some up-voted comments on this post, a way for the community to express what they think about my question. However I won't be paying any attention to them, the comments may be removed at any time, as @Jamiec points out.
So I won't add another comment but will edit this into the question.
@ Jamiec: "If its in a comment, its transient, and might be removed at any time"
- Why at a time when the question is still highly active?
- And more importantly: why by the person who may have a direct vested interest? If it appears so, why not handle things in a way that removes that appearance.