Is it the exposure to bookers and agents? Well, yes and no.  It really depends on where you are with your comedy career.  If you are truly ready for exposure to network executives and booking agents, they probably already know who you are. A comedy festival might be the perfect time to show them what you have while they are a captive audience.  Booking agents will take you one once they see you are able to be sold to their clients.  This typically means you have some credits that would make your name familiar to their clients. Also, if you can draw a crowd on your own based on the work you have put in...