I have a line of pressure cookers in my gadget pantry! I used to use them daily to make cooking faster and easier. I used one for frijoles in an hour, cabbage to al dente stage in 5 minutes with no mistakes, very lean cuts of beef in an hour, things like that.
I have been a ranch cook for more than 40 years. I fed breakfast, lunch, dinner and snacks to 50 to 100 cowboys, as traveling cook when we were working. There were about 6 different ranches most of the time working together covering some 1000 square miles of high mountains.
No, you will never see a cookbook by a celebrity "chef" honoring the humble presser cooker. But when you have 4 hours between meals, they are absolutely necessary. Crockpots may be nice, but are only good in winter when you need constant soup kettle. They don't burn so easily as stockpot converted to soup kettle on hot burner.
Yes, commercial kitchens do use huge pressure cookers to cook some foods more quickly. School and hospital kitchens use them all the time. Lunch must be on time.
I have no idea who Thomas Keller may be or what may be in his book! My bibles are Better Homes and Gardens New Cook Book and Boston Cooking School Cook Book (aka Fannie Farmer Cook Book). Cowboys don't want fancy food, just filling common food well presented.