Why else would we see mistakes like, "It's a win-win situation!"
What is a "win-win"? Is it anything like a win-celebrating sports fan? Or a game-changing decision? Or an overhead-cam engine? Or a sun-dried tomato? A hyphen takes multiple words and turns them into one descriptive term.
When you have two sides or two options to a situation, you use a slash to separate them:
Come on, guys. It's not that hard.