I guess some people are better at commenting than they are at writing their own posts. In that regard, comment rewards can be a good thing. It all depends on the sort of comments they write! There are people who write many, many comments, but they are all heartfelt and on topic.

The spammers though, they don't deserve rewards. I actually found one today and scrolled all the way down to his first spam comment to flag every single one that had an upvote.