That depends on the airline. El Al used to require them to be closed for ground operations (I assume from some I’ll-conceived “security” reason.)

It’s common for daytime ops from desert airports for the cabin crew to ask you to close them at the gate to minimize heat gain on the aircraft.

I've routinely been asked to close them once we've landed when its hot out (mostly in hot areas of the western US).

I also had that impression until a flight attendant of Virgin Airlines insisted on me keeping them closed during takeoff.