Those are only windows in the conning tower. Not a place you occupy while submerged. They are only there for running on the surface in inclement weather. That's more a matter of doctrine and preference than anything else. Now, on a side note, a lot of subs are experimenting with putting hard wired cameras outside the hulls and stitching together a virtual picture of what is outside the hull, combining sensor feeds and many other things. Then they really can fly the sub.Why do Chinese and Russian subs have windows while US subs do not?