But the roomettes have two windows, one next to the sink/toilet and one in the door itself. The bedrooms could have a window in the door, but don't.
Pure speculation, but maybe the designers decided (after surveying passengers?) that having to close a curtain over the door for privacy in a bedroom would be much more effort because you couldn't reach the curtain while in or on the bed, but in roomettes, it's a much shorter reach.
The wall opposite the bedrooms has lots of windows, but you would have to open the door to see out them. To see out the other side of the train from a roomette, you wouldn't need to open the door, but you would need to open the curtain, and the occupant of the opposite roomette would also need to open their curtain, and their window curtain, and you would be looking through their roomette to see out of the train. Maybe there is some rational reason buried in these facts for roomettes to have multiple windows facing the passage, but for bedrooms to have none, but I'm not seeing it.