It's my style to try thing personally if I can before I write about them. This makes it hard for me to learn about conventions, because I avoid crowds and have been to enough in my life (years ago).
I am interested in accounts of how webcomic creators feel conventions help their bottom line. Sure, I've read most of what's out there, but I bet different people have different priorities when attending cons, from face time with people to selling merchandise to doing sketches.
I'm interested in hearing what part of annual income people are drawing from conventions, for people willing to share such things. I'm not looking for dollar amounts, but rather, rough percentages. I imagine there would be a wide range of reports if lots of people answered, so if anyone answers, it would be interesting to hear their sense of why they have the results they do.
If I was interviewing someone on the topic, a question I'd surely ask is, Webcomics are already hard work. Why pack up all your stuff and travel to some city to hang out in a stuffy hall all weekend when you could be cultivating mail order instead?
I'm not unaware of the positives. I would like a better understanding of how they outweigh the hassle, and for everyone over 30, how you bounce back in the aftermath. :)