Window Shades.. why do they need to be open on T/O?

Maybe one for Wys or any other Pilot here (sorry, don’t know any else, still getting to know everyone).

Why is it a common requirement in the preflight and Pre-landing briefings to pax that the window shutters/shades are open?

This has always mistified me somewhat.
I know it can’t be crucial; and I’ve seen so many pictures of A/C taking off or landing with several window shutters/shades closed