And in the US prediction markets are regulated like commodities which have much more lax insider rules, because again, insider trading is the point.
And like any other gambling (see 1919 Black Sox), they can also incentivize behavior for actors who can influence the outcome of what’s being gambled upon.
Personally, that’s a significant enough negative externality for me to not want to live in a society where “prediction markets” are popular.
Says who?
I have a bridge to sell you in Brooklyn if you believe that when you bet on the stock market or on the sports market for each and every particular bet involving millions of people the maximum profit is not reaped by a half a dozen of insiders who trade on inside informations and their only problem is not being too obvious about it.
Also even if they get caught the millions of people wagering are still getting fucked because there is not a redo or making people whole when the insider traders get caught (which is a tiny percentage of the time)