If it works for you it works for you, but I'd caution readers to be skeptical when trying it out.
I agree that everyone should be skeptical and look for evidence.
For me personally it has been a godsend, that's what I can state. I also know about 5 other people who have applied this knowledge and all had noticeable improvements in various areas.
Experience may vary of course. Bodies are also different.
You can go the Buteyko way, Chi-Gung, Yoga, Wim Hoff method etc etc. whatever works if you need it.
Generally I do however think that breathing is way, way underappreciated as a cause for various diseases.
I've seen 5 medical specialists who overlooked my breathing _patterns_. I've been hooked up to heart monitoring devices, gave plenty of blood to examine and all that jazz.
The solution was literally right under my nose.
In the end it was a $5 USD discounted book about Buteyko's research that made all the difference.
Breathe through your nose, your mouth is for eating and talking. That will already help many people. :)