Another thing I'm wondering is if the video should be more appropriately addressed to (by the reviewer?!), e.g., age 55+ players (except that could limit potential sales). I think a 35 year old normally would have lots of energy still, but maybe typically would have rather limited free time to study - noting that all that may be true of typical 25+ year olds, too(!)
In my own case I'm almost 60, as I wrote earlier. When playing, my usual opening choices are many, and both tactical or positional. I simply play positional openings more often against kids who are not clearly that weak, while sometimes using tactical openings against the ones who seem the opposite (at least by rating). Against everyone else, I assume most have limited time or will to study openings too, so I play what I please; I don't play in big events too often, so I'm even less likely to suffer by using the occasional 'bluff' when it comes to openings. If I was to take a more responsible approach to my opening play and study, I suppose I'd have to shed the tactical openings in my old age (if not immediately), but then I'd be wasting a lot of experience, and previous study (however little), with said openings.
One other thing I'd note is that e.g. Timman and Korchnoi both kept playing tactical openings well into their senior years, and they were/are still a force, as Yermolinsky put it, so it appears some older GMs don't seem to worry about having less energy compared to youngsters (though as professionals they do have lots of time to study, at least).