this assumes a lot about what type of hackathon you're going to and why you're going to a hackathon. If you're going to a hackathon that's a judged competition with prizes for the specific purposes of trying to win a prize, this is accurate, but what you're really doing when you attend hackathons like that with those goals is working for the hackathon organizer without a contract, hoping that you'll get paid, knowing that most of you won't. That's not play, that's work. Is that worth it? Maybe. If it's your only opportunity to potentially get paid or you would have nothing to do otherwise or you're really motivated by competition (and not learning/fun/socialization), sure, that can be worth it.
If you're going to a hackathon with the intention of learning/fun/socialization this post is terrible advice. I went to hackathons for years. I never went with the intention of winning. I always enjoyed myself and always got what I wanted out of it. I've never placed first in a hackathon, but I met several friends at hackathons that I am still friends with years later, learned many technologies through attending hackathons, built lots of fun little projects that I'm proud of, and met my wife at a hackathon.
And to all those people saying "that's not really a hackathon", that ship sailed long ago.