Reflections from lenses make them more noticeable. Internal refractions within the lens can result in distracting reflections and "ghosting". These are particularly noticeable in bright sunshine or while driving at night. Also, bright objects behind you can be reflected back into your eye, creating a distracting double image.
These reflections can be reduced by applying a special anti-reflection coating to the lens. This not only makes the lenses look more transparent, but also helps to get rid of distracting reflections. It can also be beneficial when driving, particularly at night.