Whats the point of Sub Factions?

So think this may have been mentioned before - but what is the point of sub factions? The only effect they seem to have is changing the paint job on your ships - this isnt really sub factions - this is a fleet painter dressed up as somthing else! Or am I missing something?!

P.S - I am aware that there are some small effects for some chaos sub factions having different skills availible, but why is this limited to a single faction - sub factions should have more of an impact of the fleet / gameplay surely.

it's mostly a customization thing, the colour of your ships

@edwarddod in the last game they did something, but tindalos got lazy and only gave chaos unique skills this time (and maybe one or two others). I was really looking forwards to Necron subskills too...

@nemesor-xanxas
The second necron faction looks really dope though, and has a 5 percent to beguile self thou

@pointdexter several of the Necron subfactions are actually incorrectly colored. Not that one, but...