Well, sucks in the field, but in a CQB situation, black LBV over cadpat looks fairly FIBUA/SWAT style, which when armed with a bullpup, makes for CQB funnery.
And besides, the LBV also can carry essential supplies other than ammo. First aid kit, compass, Fox 40 Whistle, map, change of socks and underwear, candy bars, smokes, etc. All the more reason to wear one.