I don't think there is a real concrete answer. I would think topography has a lot to do with it. Even in my hay fields it is apparent how much a little knoll or knob will attract bedding.
I don't have a whole lot of experience with nwsg. My buddy owns a 30 acre field. I can tell you it is hard to walk through it. Deer avoid predators in it: I found a wolf kill a few years back. The wolf was obviously chasing this deer through this field. It was December and there was snow, so you could tell what happened. This young buck decided to leave the nwsg, and the wolf nabbed him within 50 yards. It appeared to me that deer was avoiding the wolf in the grass. I would imagine their ability to bound above the thickest portions of the grass, gave the deer the upper hand. I think this observation is worth the weight in gold. We have to remind ourselves we aren't the only predators out there. I don't know exactly what a deer thinks, but I'd guess that young buck would have had a better appreciation for that grass if he stayed in the grass, and lived. I don't know?
He also shot a massive 170" typical on a drive in a smaller patch of nwsg. This buck had large thick and nasty swamps and cutovers nearby, but he chose to wait out wi gun season in that grass. Someone had to pretty much step on him to get him going.
I've become sold. Just like all the stuff we do, it's a case by case basis. There is no magic wand like some in the deer industry convey. I'm converting 20 acres of field next year. It has just as much to do with protecting my soil, as adding cover to a part of my farm that lacks it.
I also like the way it looks. So to me, it comes down to more than just deer.