Comments are the life blood of a blog, they can also be damned useful for Internet Marketers too! Google and other search engines rate posts with a number of comments on them in their algorithms which in turn can boost your SERPs (Search Engine Results Page) ranking.
Of course spam comments are just evil, and every WordPress admins nightmare. Though Akismet does a fine job at stopping them.
Of course, if you have comments turned off (sometimes you just dont need them) then you may as well skip this section.
The Comments area in the WordPress dashboard, literally just lists all the comments on the site, with the meta details of who posted it and on what post.
There are several quick options here, including delete, mark as spam/unspam and even a reply button so you dont have to hunt the post down to reply to it!