> Or, indeed, any heavily used real prediction market.

Predictious, Bitbets and others have had some success before. It didn't work well because none of the cryptos are stable, and also - given the semi illegal nature and the need to rely on anonymous operators - exit scams happen every now and then.

Oracle is simply a URL where the info will be sourced from to resolve. For example, bloomberg.com/in/fo, or trusted.g.uy/bet12