For betting markets, the market maker may need to manage the odds differently, and for prediction markets, it’s because otherwise you’re paying people in lower brier scores for watching the games, rather than being good predictors beforehand. (The way that time-weighted brier scores work is tricky—you could get it right, but in practice it seems that last minute failures to update are fairly heavily penalized.)
For betting markets, the market maker may need to manage the odds differently, and for prediction markets, it’s because otherwise you’re paying people in lower brier scores for watching the games, rather than being good predictors beforehand. (The way that time-weighted brier scores work is tricky—you could get it right, but in practice it seems that last minute failures to update are fairly heavily penalized.)