I definitely feel that comments are a waste of time.
It also makes you water down your original message too by adding in phrases to clarify your point or by clarifying edge cases. The audience that you develop will generally know what you mean anyway.
A lot of the time it depends on the type of writing you do as well. So a lot of the time my views, opinions and conclusions counteract with others. So commentary also serves to 'hold me back' in what I want to express. It just feels like a negative force.