A winch is a big investment, so you should protect it with a winch cover. Because a winch is permanently mounted on your front bumper, that means it's constantly exposed to the elements. The sun's damaging UV rays will not only fade the finish on your winch over time, but it can also degrade your synthetic line, which could potentially cause it to fail when you really need it.
A winch cover also cleans up the front of your Jeep and looks great when installed. If you're winch is already a few years old and showing it's age, a new winch cover can hide it, for a cleaner look.