Hopefully this is an easy question to answer. I use the blog feature as a way to manage content on my site by category. It's more flexible for adding new content -- rather than adding new pages.
That said, I have a site where I have two distinct needs for a blog - an "Articles" blog which is where I write and publish. And an "In the News" blog which I want to use for the display adding summaries of relevant news articles. I want to keep these separate as one is really internally created content -- and the other is summaries of external.