High probability contracts require you to put up a lot of capital to make a small profit. This would be fine for a bet that has a quick turn around, but predict

High probability contracts require you to put up a lot of capital to make a small profit. This would be fine for a bet that has a quick turn around, but prediction bets often require the bet to be placed well in advance of the event, which means the capital is locked up for a long time.... it is basically a low interest loan to the bookie.