Do you really think that the chance is 50/50? Here are some factors to consider: 1) The difference between popular vote vs electoral vote. 2) Hillary at the same time in 2016 was leading by 80% but we know how the polls were off 3) Kamala is outspending Trump 3:1. 4) The election is determined by votes not bets.

Hence, this is a great arbitrage opportunity if despite above factors you think that Kamala will be president.