I can't really imagine not being look out a windows during the day. Also I think I'd feel trapped without windows, not that I can just jump out my 3rd. floor window.
Sunlight is nice if I'm going to be outside admiring nature, but it's crap for reading, playing video games, any number of activities I want to do at home.
The cheap place I'll be staying on vacation in a couple of weeks offered a "free upgrade" to a room with a window and I was like "I don't understand - what would I in theory see out of this window?" because it's in a city centre, and obviously as a tourist I shall go out and look at museums and galleries and stuff, I shan't be sat there all day looking out the window, so it seems pointless. The other person I'm going with likes windows, so they'd already paid a little bit extra to have a window anyway. Crazy.
On a side note I don't think I'd stay in a hotel/motel room without windows, that just seems creepy. For the same reason I don't book room on ferries without windows, even though I'd just see the water.
As an employee, I hate this rule and would love a windowless office. Right now, I just keep the curtains closed all day.