Keeping the window shade open allows flight attendants and passengers to spot any problems, such as an engine fire, immediately and alert the flight deck.
In case of an emergency evacuation, open shades help the crew assess whether it is safe to use the exit.
Open shades allow employees outside the plane to see and evaluate the situation inside the cabin.
Having the shades open enables your eyes to adjust to the outside light, improving your visibility during an evacuation.
Passengers can also assist in identifying and reporting any unusual occurrences outside the aircraft, enhancing overall safety.