# How skew in vertical put spreads change the payoff?

An spx four strikes wide Put Spread from at the money has a payoff ratio of 1 to 2 meaning if the Premium on the spread is \$10 your reward is \$20; yet the corresponding Call Spread with the same width from at the money have a payoff ratio of 1:1 and I know it's because of the skew on the put (downward) side.

But both have the same probability, it's like a Roulette table that pay 2:1 on black and 1:1 on red. So my question isn't this an edge for any one taking the Put Spread?