Thanks, that explains a lot and makes sense; but then makes me wonder why some people use a hatchet, and others just wring the neck and kill them first.
Different people and different religions and different cultures and different traditions have very different opinions about poultry processing. And the person doing it has to do what works for them.
Science suggests a killing cone helps calm the bird from being upside down and being gently squeezed. This means less stress immediately before death, which means nicer meat. The cone helps reduce thrashing which helps reduce bruising damage to the meat. A thorough bleed out produces better meat. So ...
It isn't that hard to pull the head off a meat bird, but I don't know any advantage of doing it that way beyond personal preference.