I have seen again and again cases in which a comment consists of a perfectly valid answer, something that has already been discussed here. In my opinion, no matter how simple an answer is, the person who asked the question should have the opportunity of declaring an answer as the accepted one, so that someone else with the same doubt may know right way that the answer as been accepted. Yes, the person who asked the question can post a comment declaring that the other comment contains the answer, but it is not the same thing IMHO.
I don't think that my question is the same as the one to which I posted a link, because what I ask here is if the users of Math.SE should be encouraged to always post their answers, even when they are very simple, in order to give to the person who asked the question the opportunity of marking the question as the accepted one. It is a matter of etiquette. The other post is about the possibility that a question without accepted answers will continue to be bumped by the robot.