I agree with rm-rf. In very dark conditions I need very little light once my eyes have fully adapted. OTOH, I want a much brighter light when surrounded by distracting lights and in order to stand out.
One of my few crashes occurred when a motorist didn't notice me while focusing on the headlights of cars behind me. As a result he pulled out into my path even though my headlight was shining in his direction. It's also why I want a flashing or pulsing light in urban conditions to stand out from other lights.