Bettors have money in the left side of their chests. That's why politicos see bettors behavior as a useful metric alongside (or in place of polls). Who you going to trust more to tell the truth, a guy who takes a random call and answers a few questions on the phone or a gal who lays her money down in a Las Vegas investment bank?
And so it matters, just like the Reuters/Ipsos poll cited earlier matters, that in RCP's average of betting behavior 50.7% of the money is now on Kamala Harris to win the presidency, compared to 48% on Trumpie.