Effect on POI when occluding red dot sights

[Uncas47]

This would potentiallu allow for a *lower brightness setting and longer battery life, as well. The dot is against a black background.

Exactly. The gun by my bed has been covered for years, guns that go outside remain uncovered. I'm not recommending this to anyone, it's just how it works for me. I have both eyes open all the time and focus on what I want to hit, it makes no difference to me covered or uncovered.
ETA: My comp M4s have the ARD screwed in which seems to help keep the brightness fairly constant and I'm used to shooting with those also.