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?
I’d sleep way better and wouldn’t need blackout curtains
But then you wouldn’t be able to naturally wake up in the morning, which is best triggered by light much as the release of melatonin is triggered by darkness.
Most people need to work in the winter, too. It’s still dark outside in the morning either way, whether my eyelids are translucent or not.
You can make it a lot easier to wake up in the winter months by getting a sunlight clock.
I don’t wake up to the light though
It helps with waking much as darkness does with sleeping, but it similarly is not going to be enough to overcome under sleeping or a sleep disorder.