I think they are useful to let people know how their comments are being received. If you just have popular/unpopular then you don't know if it was just one pers

I think they are useful to let people know how their comments are being received. If you just have popular/unpopular then you don't know if it was just one person or multiple that disliked or liked your comment. Getting downvoted or flagged on a comment isn't fun but it is important in understanding the community and how to interact with it. Ultimately every person needs to manage how they use HN so that it is a resource useful to them rather than a distraction.