This is probably as toxic subject as whether people are allowed to recline on their reclinable seats or if the flight attendant call button should be used for non-emergencies such as ordering refreshments.
Well. I was on a Philippine Airlines Narita to Manila flight last week that left around 10AM from Tokyo and was scheduled to arrive 2PM.
I was bit surprised that after the meal service the FAs were asking people to close the shades. I was typing away with my laptop and prefer natural light and thus declined. This threw the crew member off. Don’t think that request such as this is something you must comply with. I was sitting by the window and had the other two seats unoccupied.
You can recline in or use the flight attendant call button to order refreshments if you so feel.
The only reason why crew would like PAX to close the shades during the daytime flights is to put them to sleep and not having to offer any services. The request was delivered in more as an order……
If you are sitting by the window, it is up to you when you want the shade(s) to be open or closed. I prefer natural light and occasionally daydream while looking at the clouds/sunset/sunrise.