Prediction markets are real-time, but World Cup TV broadcasts have a delay of dozens of seconds—that's the profit source for many people. If you have faster data sources (like watching live/in-stadium real-time APIs/low-latency streams), you can trade immediately after an event happens (like a goal/red card). Most players watching on TV are in a 'lagged' state, and the market prices haven’t adjusted instantly. Some people can buy/sell at 'wrong' odds and then close their positions for profit once the information spreads. Information asymmetry creates delayed arbitrage opportunities.