I would concur with what many previous posters have said (easier to fall asleep or to relax, making IFE an overall better experience...) but I would also add that the sleep I get is a better quality one. I always manage to fall asleep in a plane but with the NC headset (currently QC25 but it was the same with my Audio Technica ANC9), I usually feel fresher and more rested than I would do after a nap without those.