Geometry is a lot of it. It also makes seeing much easier when pulling out. When backing in, I can easily see the traffic lane around me, and they can see me pretty easy as well (I’m the asshole blocking up the whole place). When driving out, only a smaller portion of my vehicle needs to enter the traffic lane before I have a clear view of any opposing traffic. For the case of nosing it, I have a clear view while pulling in; but, when pulling out I need to get most of my vehicle out into the traffic lane, before I can see anything.