It is a technique used by high altitude climbers probably confused over another type of pressure breathing you mention.
Maybe controlled breathing to maximize oxygen intake maybe a better description.
There is nothing wrong with controlled breathing uncontrolled breathing as in hyperventilating is far worse.
Scuba Diving we use controlled breathing to maximize bottom time and to use as little air as possible.
Yes this would be different again where you are maximizing oxygen intake in high altitude situations but I cannot see why it cannot improve matters.
Pace