Hey, mate as far as I’m aware, comments sections are really good for SEO. They create unique content and enable your page to show frequently updating content too… all of which is Google friendly. In fact, google loves fresh and unique content!
The only thing you should be aware of is spammers, however, using your settings you can make it so that comments are only posted by your permission. In other words, you will have to approve the comment before it is shown…..
Hope that helps