Like he says in the video, it's mostly for entertainment and not for hard results.
For what it's worth, I've had excellent results (and so far, longevity) from the Walmart brand batteries. Purely anecdotal.
The video was useful enough to demonstrate that there aren't large differences. Declaring a CCA winner is a bit beside the point that all were still in a range needed to start vehicles which spec those battery sizes.
How long they last is certainly important yet beyond the scope of a youtube video. We might assume an AGM would last longer, and yet I am more interested in having the prorated warranty past 3 years, so it is covered for about the amount of time I want to get out of a battery for the money paid. That makes the JC/Walmart Everstart Maxx batteries an even better value to me.
Really, the point of the video is about the only point that can be made within a reasonable amount of time. Driving cycles, individual vehicle charging characteristics, climate, and other factors present far too many variables to pretend he could just do XYZ and end up with a comprehensive test methodology.
Anyone who feels he should buy 6 identical vehicles and drive them all exactly the same amount on the same schedule for years, then repeat with groups from a different make/model vehicle, in a different climate, and all of these in different driving cycles, then repeat the tests so there is more than one sample of each state, then repeat this for every possible scenario for hundreds to thousands of years (one man can only have 24 hours in a day) is welcome to do that him/herself.
The main thing to take from the video is that you are wasting money if you're paying more for the same or an inferior battery, if there is nothing additional you are getting for the money. With AGM it may be lifespan but with the others, the only reason I can see not to buy at Costco or Walmart is either convenience or that you don't want to patronize one of those companies.
Personally, buying a battery is the only reason you would find me at a walmart, but I love that I can go to my local WM 24/7 and grab a battery off the shelf even if the automotive dept is closed and I have to take it up to a front checkout lane to buy it.