This is just one of four exercises BP Zone he mentions, the idea behind them is to stretch your body to its limits so that it becomes used to working in a more demanding way. Conditioning yourself by practising breathing exercises will slowly begin to improve lung capacity and the ability of your lungs to perform more efficiently.
The good thing about improving breathing technique is that as long as there is a conscious effort particularly in the early stages to actively work at it you do not require any musical talent to quickly progress to a much better level. Keeping physically fit will only help improve lung capacity and efficiency and it is strongly recommended. Playing the trumpet is akin to being an athlete and you need to be fit to play it to your maximum potential.
Breathing therefore should not be ignored and in fact should be actively taught and re-emphasised to students and teachers alike. Many other playing problems can be traced back to poor breathing and I truly believe that it is a fundamental core technique that is not difficult to practice or become proficient in but is something that many don't ever work on and as a result never reach their full potential.