Question About Hedge Funds?

What’s the point? I don’t get it.
I mean, I understand that people get obscene amounts of money but, for what? Like… Bill Gates has Microsoft which makes computers and programs (word, excel, powerpoint, etc) that people in society use as tools. Cool. Mark Zuckerberg with Facebook, again another tool. Nice. Then you have medical doctors who make a living healing people and saving lives. Teachers who help initiate kids to go forth and lead their lives.
But a hedge fund? What do they DO? What is their mission? What’s their societal contribution? I honestly don’t understand. Is the end goal simply just money?