iPhone X - Safe Area does not achieve full-screen experience?

Actually I believe the answer is this: to accomplish full screen we should NOT use safe area support. After I unchecked Safe Area Relative Margins and Safe Area Layout Guide on the view in Interface Builder Size Inspector I got the expected result:

In fact I would say that the idea of Safe Area is that of an area which will for sure not be overlapped by any of the system icons, or rounded borders, full screen is the opposite of it.

Just change your bottom constraint First Item to SuperView