I've never annealed any rifle brass. Been reloading 30-06 brass for over 30 years, and have some that's just about that old. It's never been annealed.
Cartridge brass is made from a special copper alloy, and is made to be stretched. The product actually starts off as brass sheet (flat) and gets punched extruded to form the cartridge.
For casual shooters, the annealing step is worthless. If you get a cracked (split) case mouth, which is where it normally appears, toss it. The slight cost of a tossed piece of brass is nothing compared to the cost of all of that fuel.
And, if you pay attention to the notes inder the video, you'll see that plenty of people have correctly pointed out that the brass is being OVERHEATED. Virtually just a slight touch with the flame, preferably directly from the top of the case, rather than from the side like in the video, will give the fastest and most concentric annealing. The slowness with which the metal is cooled is almost as important as the heating.
Having said that, any brass which is annealed will DISTORT due to irregularities in the grain structure of the metal, inherent in the manufacturing process. I don't know about you, but I don't want distorted brass in my gun. Sure, you can straighten out the distortion by running it through a neck sizing only die, but why bother?
Skip this step, and just toss any split cases.
I'm guessing that the guy doing this in the video has only 100 cases to his name, and is on a mission to reload them 100 times each. I'd rather have a thousand cases, and reload them 10X each.