Window blinds can be up or down for landing or take off but thoes on a door have to be up. Cabin crew may ask passengers that are seated adjacent to an exit to put theirs up also as it is important for the cabin crew to be able to see outside if nessasary. ie if an incident happened.
Some airlines may adopt different procedures to this however.
On a night flight the blinds are put down to stop the sun waking passengers up on a night flight. Because of the time changes sometimes it could be 3am in the morning for thoes sleeping but actually 6am outside where you are flighing over so therefore the sun would be very bright and low and it shines directly into your eyes.
Daytime flights are different and mostly it is left up to the passengers but if the sun is low or very bright it can affect the video screens so maybe this is why Cathay do this.