I think you are looking at it the wrong way, Is the OHS good for size/hypertrophy? ABSOLUTELY, if not directly than indirectly, That is like asking is drinking water good for hypertrophy, well....if that is all you did, then no,....but when you train for BB and you drink plenty of water, its going to make a PROFOUND difference if you drank little or no water.
Roger Benjamin, who was a world record DL holder and owner of the Lincoln Health Club where I grew up used to get asked by bb'ers all the time about what to do to grow a certain bodypart, for example they would say, Roger, how can I get my chest to grown and he would say, you have to eat chicken breasts because its the same type of meat,,lower body, chicken things, arms, wings, lats--babyback ribs or backs of chicken,,,,,he was just messing wit them, but they believed it and actually tried to eat that way. The human body does not know what bodypart you ar trying to feed, it feeds the whole system.
Will doing barbell rows help your max squat? ABSOLUTELY.....just not directly. As DJ says, the OHS makes your body into "once piece" ie, it ties is all together
Historically, the best bodybuilders in the world, achieved their foundational build by doing heavy, basic work, ie, they tried to get stronger,,,look at the list of Mr. Olympias, with 1-2 exception they were ALL known for their strength and being stronger then their peers.
When you use strength training to build a foundation, you get a much more solid look and I find you tend to hold the muscle development a lot longer than if you tried to "pump" your way to fitness. I cant tell you how many times I have bb'ers who avoided heavy work and avoided squats, deads, etc and they got their build though a lot of isolation work and pumping, they achieved the look, but if something happened, say an injury or an illness where they could not train for a few months, they would literally lose most of their gains,,,the guy who trains heavy (be it a bb'er or otherwise) stops training and can hold the development for a very, long time, I have seen this so many times in 30 years of lifting.