This is a point dozens upon dozens of other users have already expressed. There is no way it's "supposed" to be used. We're all free to use it how we see fit. Having said that, think of it as a courtesy for someone giving you a reason for their downvote. It's not required, but it's courteous. Just like holding a door for someone in public is courteous. It's not required, but if you don't do it, some people might think you're being rude. Really though, none of us are in any position to complain about the amount of FREE money we get here.