As someone else said, it’s a betting site, and the numbers it is showing are based on how much has been bet on any given candidate.

I think it’s fair to say that it’s not a reliable indicator of actual odds. It’s essentially a money weighted poll from a self selected population (people who would use an online betting site to bet on an election). So, it is not a good random sample of American voters, let alone a random sample of voters from swing states that actually decide the outcome.