How does comment voting and flagging work?
Usually when our answers get upvoted on Stack Overflow, we earn 10 reputation points. Similarly, are there any points awarded for comment upvotes on Stack Overflow?
Apart from a good feeling there is a silver badge:
Pundit - left 10 comments with score of 10 or more. This badge is given once. It has been awarded 37 times in meta and 128 times in SO, so it's rather exclusive.
No points, but your upvoted comment stays visible when there are many comments on an answer, such that non-upvoted comments get hidden.