To roll your boat up again is an essential skill to save time or even your life.
You can use your paddle to pull yourself up or you can learn the fine art of rolling up just using your hands.
The hand roll is a method of righting a capsized kayak without using a paddle,
but using the floatation of your upper body along with resistance from your hands and arms to allow a strong hip snap and delicate body positioning,
It returns your body weight to the kayak's centerline quickly by throwing an arm or sweeping your torso.
It helps to gradually reduce the size of the paddle while practicing, ending up with a pingpong paddle or webbed glove, even a plastic bread bag will work to increase resistance, until finally you are able to roll back upright holding nothing but water and a giant sized grin.
While there is an outside chance you might need to use this roll someday, its main benefit may that it is a method to improve the technique and reliability of your paddle roll. That and its a great way to impress your pool buddies, even if you don't know the first thing about a foreward stroke, they'll think you are a kayaking god.