I prefer ambient, warm/orangey, cozy lighting to fill in the darkness. Don't need 100% bright, but how do I put it? Enough lighting to see and know who I'm enjoying.
It can be a tease actually. I'm sure even if you have banged the same girl many times, sometimes, you will notice something you never did with the different lighting.
Bright daylight romps are different, meant to be fast and quick. Warm lighting at night or in dark rooms fulfill a different erotic sense.
That's why some use candles.