Why even have these non-professional outlets Because conference attendees are human. Not only are they human, many of them young. And humans like to have fun,

Why even have these non-professional outlets Because conference attendees are human. Not only are they human, many of them young. And humans like to have fun, which include boozing, dancing, socialising, and -- for many -- hooking up (a surprising number or researchers end up marrying other researchers, in my department probably about 1/2). Presenting a paper is great pressure, and once that done ... time to celebrate. Conferences are a great opportunity to see old friends. In 20 years of being an academic, I've never once been to a conference that didn't have social events of some sort. Official events are often followed up by private socialising. Indeed, making friends is in some sense the most important function of conferences. Who wants to work with somebody they don't like?