I have no doubt that scent control provides some help (maybe 10% or maybe 0.05% or less, LOL), but for my kind of hunting, it just isn't worth the time and expense of the preparation and products or it to be cost/hunt effective. I have been busted by down wind animals and up wind animals. I have made plenty of successful stalks on down wind animals and up wind. Scent control is not something I have seen to actually improve my hunting success in a notable manner. I have done the shampoo/soap, detergent for my clothing and even have not one, but TWO ozone machines. I saw no improvement in my hunting success using these products over time as compared to not using them over the same period of time.
I do get busted less when the wind is in my favor. Some folks would argue that is proof that scent control is necessary. On the face, I would agree, but when you are upwind your sound also carries towards your prey. Wind is both a scent and sound issue and we have no way to know whether they smelled or heard me, first, or which one was the determining factor that caused them to run or not run.
Just killing deer, such scent control efforts may not be required. Killing BIG deer, repeatedly, w a bow, on public land..........hard to argue with the guy's success.
Hunt however ya want.
Actually, it isn't, not if the argument of his success is due to his scent control regime. This is far from the only thing that he is doing to be successful. I noticed he has a lot of camo. Maybe being invisible to deer is the key? I bet he is good at noise control and is very good at limiting his movements and moving slowly and smoothly. My guess is that he is a very good shooter and knows when he should shoot. He probably does a good bit of scouting ahead of time, as well.
So if scent control is making a difference (and I do believe that it must have some impact), then you would think that this could be quantifiable somehow and it isn't, I think because of all of the other factors that can't be known or accounted for. As such, it has near religion-like qualities about its control. You can't put a number on it because so much is just unknown. You don't know if a downwind buck stopped and turned its head and looked "right at you" because it smelled you, heard you, spotted you, OR maybe smelled, heard, or spotted something else of interest from your direction, but not you. You don't know if your scent control totally hid you from the deer or made the deer think you were farther away and hence not a threat. You don't know if the scent control did nothing or bought you 1, 2, 3, ...30...90 seconds more to make your shot before the deer was apt to bolt. If the buck did bolt, we don't get to later ask it why it ran when it ran.
Maybe your scent control worked well enough to buy you 4 seconds of broadside, stationary, confusion on the part of a nice buck before it ran away, only as a hunter, you don't know any more than what you are witnessing in real time. Was scent control a success or failure? For most folks, that would depend if they managed to take and make the shot before the buck bolted.