Is this rendering the page remotely and fetching it? If so, it seems like the only point would be to reduce the server load on their end.
> Do you really need the contents of the newest blog posts to be pulled in each time you want to test a CSS layout change?
You would need something. At the minimum a "Lorem ipsum ..." to see how the text flows. What better than the real content for that? Especially if you already have it.