WordPress official website provides free web hosting as well as a built in social network of WordPress blogs on its servers. There could be many benefits of having a self hosted WordPress blog on another web hosting server, providing better customization options, flexibility and scalability of monetizing your website. If you are switching from blog to a website using Bluehost, you can actually keep all the comments on your posts by exporting the content from old one to new one.
Read more about the same at http://science.opposingviews.com/import-comments-wordpress-bluehost-23085.html.