From my experience, different people view Hackathons differently. I wouldn't want to make any blanket statements about why one should or shouldn't go, or what the focus should be. I don't really think there is anything wrong about being competitive and wanting to win. I think what's important is recognizing what you want, and building a team of people that match. Some people will be competitive and serious about winning. Others may be more laid back, and just want to enjoy the experience. Some may want to actually create a product and start a business. Others may just want to work with new technology, or learn something new. Building a team that is aligned with your views and expectations is important. If you don't build the right team, the experience can become frusturating. In extreme cases, it might even pull the team apart.