Is it polymarket presenting this ability to detect insiders? Or is someone trying to sell the service of detecting insiders to those wanting to know if bets are on equal footing? (or wanting to follow insiders? or wanting to hide your identity by making multiple accounts? Are there per-account fees, when polymarket might encourage people to make multiple accounts?)
Regardless, polymarket seems to be on balance corrupting, by monetizing and normalizing use of inside information, which violates agency principles. It's not clear that it really offers hedging or predictive benefits.
When trading firms do better (after data discovery and analysis), there's some evidence they're better than other firms, and you can trust them with some money. But when there's a public prediction market, the only benefit is to the insiders.