I share this perspective and hate the straw-man from pro-prediction-marketists that those opposed are moralists and puritans who can't accept that people like to bet on sports.

Prediction markets are a way of effectively placing a "bounty" on something you would like to happen. Or capitalizing on one of these existing bounties because you're able to affect the result. It's a way to commodify power (and information of course, which is what these platforms bill themselves for), converting it into money, which can you can build further power with.