The primary benefit of having comments on blog is it helps you build “engagement” with your audience. Perhaps the best way to do that nowadays is with FaceBook comments. For a  good article on why….

5 Reasons WordPress Users Should Switch to Facebook Comments – WPExplorer

When you allow visitors to make comments on your WordPress posts, you’re increasing engagement, nurturing a conversation, tempting people to come back, and prompting others to generate buzz about your site. All of this is great news if you’re looking to build an online following. Fortunately, WordPress offers several plugins that make commenting easy.