If it all goes badly wrong on take-off or landing:
Although your eyes will not be 'fully' accustomed to the relative darkness (takes about 30 mins), even a minute or two will be a big help if it suddenly goes dark.
In those dark moments, you will be able to see the 'floor level lighting' to help you to the exit.
A little ambient light through the windows (if the blinds are open) may help your orientation, as the aircraft may not be upright.
Parts of the sky, or the airfield lighting, or fires outside, may also guide you to a suitable hole in the fuselage, if your eyes are just a little accustomed to the dark.
Such little things may make a difference when it matters.