Waxed skis ski better. Waxed snowboards ride better. Period.
Wax puts a barrier between your skis or board and the snow, which enables them to move more evenly, smoother, and faster as you move down the mountain. From corduroy to corn snow there are so many different types of conditions that can exist on the mountain and there are waxes designed to optimize the performance of your skis or board during those conditions. Think about the last time you skied through a puddle and felt your skis slow down. A good coat of wax can help mitigate the impact of variable conditions and ensure even, smooth performance from your equipment.