The idea might seem uncomfortable, but realize that on airplanes today most windows are closed for the majority of the flight and people seem perfectly alright with it.
“Majority” is not all. Even with a few windows still open you can still get the sense of the outside, and light shifts as the plane moves, etc. There’s a big difference between “majority” and “all”.
Emirates (subject of this thread) almost exclusively flies super long haul overnights. Their proposal wouldn’t work for the domestic 2-3 hr hops, but does work well for that 12 hour flight where one person trying to look outside wakes the whole cabin.