Haha, pressure cookers aren't really a secret. They are found in most households in India. In the U.S., for years there was an irrational fear of pressure cookers exploding so they never really caught on until the Instapot came along (which some people don't realize is a pressure cooker). The fact is, pressure cooker tech is very old and remarkably safe. It's been "beta-tested" by millions of people in India.

The science is simple: water vaporizes at 212F/100C at atmospheric pressure. But if you increase the pressure, the boiling point increases [1]. This means instead of cooking temperatures maxing out at 212F, the cooker lets one achieve higher temperatures. This is why pressure cookers are able to cook faster -- the temperatures are simply higher.

Meats cooked with pressure cookers tend to come out more tender (if you don't let them dry out) in a shorter amount of time.

[1] Water phase diagram. Notice that on the vaporization-condensation part of the curve, when P increases, the T crossover point also increases https://courses.lumenlearning.com/suny-chem-atoms-first/chap...