Currently, if your eyes are closed you can still get a sense of the light around you, and moving your head around you can tell if you’re moving it toward or away from a light source (barring maybe if you’re outdoors and it’s bright out all around you).
But what if when we closed our eyes it was like full blackout? Would blinking become disorienting? Could it mess up circadian rhythms? Something else? Or would it not really matter?
Nothing would happen. You blink for a fraction of a second.
Also, note that the eyelids of people with darker skin already pass less light than those of people with lighter skin. (That is the purpose of darker skin)