Some people have no interest in writing blog posts. I think they still add a lot of value through comments and sure be fairly rewarded for doing so. Everyone can respond to the content others have created and it can be fun to do so if you find an author you appreciate and wish to share ideas or what you liked or wished would change about his or her blog posts.
When you write over 50 comments that have responses thanking you, but a total of less than a dollar, it makes you question if the time you spent writing the comments is highly valued. (Still far better than you would get on other social media, but out of fairness to those who only wish to write comments and those who spend a fair amount of time doing so, I believe that the rewards should be a bit higher in general).