The designers wanted it to be comfortable

I think it's funny when people criticize the D for looking like a luxury hotel in space. You've got crew deployed on this ship potentially for years at a time. Of course you're going to put some wood paneling, beige and pastel colors, and potted plants in there. Would you want to spend every waking hour looking at gunmetal grey deck plating? Spruce the place up a bit! Saves money time and effort on dealing with all the mental breakdowns.