Prediction Markets Suggest Replacing Biden

Why should we care about ‘prediction markets’?

Not only they are obviously highly speculative but also prone to easy manipulation by insiders (likely in this case both Biden and Trump associate/aide insiders) which are the only people who make money.

I remember when PredictIt shutdown and yet we have polymarket (gross crypto prediction market) and others encouraging people to gamble while insiders are allowed to rig the market.

So I’m curious why prediction markets should platforms should exist at all.