IMO prediction markets are an interesting tool but you can just ban sports gambling and keep 100% of their value and remove 90% of their downsides.
I'll be honest as someone who doesn't gamble my perception is the prediction markets are just people with inside information using that to con money out of people. I don't see the value in it.
You can also ban 100% of gambling advertising and get 100% of the (dubious, but I'll humour the possibility) 'benefits' of gambling, while removing 90% of the downsides.
Prediction markets are 90% sports gambling.