Why do you need performance sunglasses?
All sports require you to react to your opponent, the environment or an action of some kind. If you are driving then the conditions change. They change depending on the time of day. The change depending on the weather. To keep up with the conditions of your environment it is important to wear the correct sunglasses.
If you are around water you need polarised lenses. If you are at altitude you need category 4 lenses. If you are driving then photochromatic lenses will certainly help with changing light conditions.
Performance sunglasses are important for protection and important to make sure you can see correctly. If you are talking a walk, riding your bike or climbing Everest. You need to wear eye protection.