Correct. There are no costs involved, only the time it takes to be approved. This can range anywhere from a couple of days to a couple of weeks or more depending on how many apps there are to review and how busy John is. Your site must meet certain requirements which are mentioned in the membership forum on their board and you must sign an NDA as well to access the private forums.
I stopped visiting when I took a temporary leave from this business (thought it’d be permanent when I left). I stopped by there the other day but didn’t login. Was neat to see they were using one of our board skins though, heh.
I can’t really say if there’s an extra benefit other than having access to the private forums.