Aren't there more legitimate use for some of these for hedging? I don't know any specific examples, but I'm sure I've heard of situations where people use these

Aren't there more legitimate use for some of these for hedging? I don't know any specific examples, but I'm sure I've heard of situations where people use these because they want to invest in something quite specific, but remove the upside or downside of general market movement. Regardless, I'm inclined to agree the main point is probably gambling and insider trading.