Polarized sunglasses have a special coating that blocks out glare, and helps you see things more precisely when you’re in bright light. They are designed primarily for fisherman and other people who are on the water frequently. They’re also good for skiers and snowboarders when they’re on bright white snow.
There are people who swear by them and will only wear polarized lenses for driving and other activities that require their attention in sunlight. Others are not so pleased with them, and they prefer to have glasses without polarization because they feel it causes impaired vision. It’s entirely a matter of personal preference, but polarized lenses will reduce the glare you get from water, snow, cars and concrete.