I've always been a sucker for visualizations that show the relative scale of things. I think it's good for all of us to realize just how fragile and insignificant our little planet is. This image certainly accomplishes that.
The larger planets and Sun just bleed off the page, but still give a sense of scale by the visible curve of their limbs. And where to cut it off on the small end? Why 200 miles? Well, that's entirely arbitrary. It so happens that I have a fondness for Saturn's moon Mimas (247 miles across), and 200 was the next round number down. That simple. Also, it captures a fair percentage of known Trans-Neptunian Objects (51), enough to give a good idea of their place in the larger scheme of things.