I did it for both reasons on my truck...thought it would look good w/ the reverse lense covered, and it does IMO, and thats all that matters to me. Its different and looks good in my mind, so it goes on the truck. I think these were the stock lenses too, so they were 13 years old or so, so they did need some shine added back to them...and i just like how dark mine are too...that is the best $10 ive spent on the truck in a while.