I actually just noticed a setting on mine now that you mention that. It is to set it so that the comment is auto-approved if the person posting it has already had a previous comment approved, if it is a first time commenter on my blog, then the comment will have to be manually approved. I have mine set to this now.
While I've not managed a blog in a very long time, I've always had manual approval set for blog commenting. Even with having a couple different types of anti-spam add-ons installed, there always seemed to be a little bit of spam coming through, so this feature keeps that in check.
Years ago when I had my blogs, I would manually approve comments on them. On a few of my blogs though, I totally disabled commenting. I got tired of having to verifying if every comment was legitimate or not.
My blog is, not that active averaging 6-10 blog comments a week. Even though my blog isn't overly active, I'm getting a lot of spam bots which are registering, spam can heavily effect SEO(search engine results) so I have decided to approve each comment manually.