Sometimes in a answer, when OP asks for some moderation of code or discussion about some point of code that given as answer, then we explain that or a give small piece of code through that comment so that OP can understand.
It would be better to give some features in comment section especially code tag, text block/strong/may be italic and bullet list options.
Also, after 5 minutes editing in comment is disabled automatically.So isn't it helpful to extend it? Because conversation in a question and answer may be longer than 5 minutes and editing may need there as per requirement.