What’re the strongest reasons why prediction markets need to be built on crypto rails?

They’re one of the canonical smart contract use cases and I find myself increasingly using them to understand world events, but it’s not clear to me if Kalshi or Polymarket have the better approach

Why does anything need to be built on crypto rails? Bc public permissionless markets are best suited using crypto

I think their approaches differ mainly bc of the regulatory regimes they operate within.

Kalshi plays it much more conservative while Polymarket is more open and free which aligns more with crypto ideals