This technically isn’t even a method. Rather it’s the opposite of a method. But I made reference to it in the gâteau battu series I did (which seemed to go on for months). The “blitz” method is simply shorthand for putting everything in the mixer bowl at once and turning on the machine. See what I mean about it being a “non-method”? There’s no methodology to it at all!
However you see this sort of thing quite a bit in the bread kitchen, notably with enriched breads like challah and (sometimes) brioche or a “cake” like gâteau battu. Because time is of the essence in bread bakeries (lots and lots of mixing to do each evening, donchaknow), extra ingredients like fats, sugar and flavorings are occasionally just dumped into the bowl with all the other dough components. Mix, transfer to rising container. Next!