I'm sure Scott is just dreaming whistfully about this, and who am I to deny him that. But lets pretend for a moment that it is a serious topic.
How many franchises get there very own conventions? Star Wars, Star Trek...basically the multi-biollion dollar operations. Everything else just piggy backs on the generaic sci-fi, pop culture conventions. Other wise four people wll show up. FOUR.
If its part of a bigger convention then SC gets exposure to lots of other folks who will swing by the booth and check it out.