As stated that pic is in no way anything concete as to what stage that ship was in at the time of painting and when things things were primed. Things get built,test fitted, puttied, primed etc. Who know what stage that thing is and the final color coats went down.
The main advantage of painting the whole thing black is that it can get rubbed down and the nice black edges for weathering to come through naturally.
The uniform color point is kind of moot... any differences in dark panels can be controlled by painting, weathering, scuffing, etc..
Lynn