I personally think that sitting in a room for 2-3 days expected to stay up and build an app/website in order to win some sort of prize/job in the end is not very useful for anyone. Almost everyone that attends says they are exhausted by the end and because of the pressure of needing to produce something quick, you tend to consume unhealthy food & beverages in the process.
I realize that this might be an unpopular opinion but I am open to having a discussion.