IS THE HALF-HALT ONLY FOR DRESSAGE?

I have a question.

In dressage, almost every teacher and trainer talk about the half-halt. It’s used as a backbone of dressage in training. It’s intended to aid in a horse’s balance/straightness, softness, and preparedness. A lot is written and videos are devoted to understanding and training the half-halt. So if the half-halt is so important, why don’t other disciplines incorporate it into their mainstream training? Why do they not consign as much importance to teaching the half-halt as dressage does?

No matter the discipline everybody wants their horse to exhibit softness, balance, and preparedness. This is especially true in competition and at higher levels. I have come across scores of dressage experts discussing the half-halt, yet I can’t recall it ever being brought up in my research about reining, polo, hunting, ploughing, mounted archery, barrel racing, western pleasure, cow working, games, trail class, etc. 

I don’t doubt there may be exceptions where a handful of reining trainers or polo trainers might teach and practice the half-halt, but it certainly is not part of the mainstream. Whereas, in dressage, the half-halt is a mainstream training tool.

Why is the half-halt mainly confined to dressage? Do other disciplines have their own version of the half-half under a different label?