In my life and career, I've found deadlines make the best mentors.
In addition to the other commenter's great point about making connections and getting exposure to different paradigms, with a tight deadline you learn how to quickly research and implement new things, and how to make quick creative decisions.
You learn when something is "good enough", and after a few jams you start to understand the holistic process of conceptualizing, actualizing, deploying and collecting feedback on games.
After a couple years, you'll find yourself more knowledgeable than the average graduate in game design, and will either discover what you'd like to specialize in, or realize you enjoy and want to be involved with the entire process.
In addition to the other commenter's great point about making connections and getting exposure to different paradigms, with a tight deadline you learn how to quickly research and implement new things, and how to make quick creative decisions.
You learn when something is "good enough", and after a few jams you start to understand the holistic process of conceptualizing, actualizing, deploying and collecting feedback on games.
After a couple years, you'll find yourself more knowledgeable than the average graduate in game design, and will either discover what you'd like to specialize in, or realize you enjoy and want to be involved with the entire process.