My understanding was that third person was implemented to make up for the lack of peripheral vision that 1st person provides. Regarding the OP screenshots, it makes up for not being able to pull yourself up the fence so only the top of your head pokes over, jump to see whats on the other side of the door, and stick your head around the corner so just one eye is visible. I know with the third screenshot you can use Q and E to lean but I find it difficult to get it so only a fraction of my face is visible instead of half my body.
