AFAICT, it's a tool to achieve your goal on your unique peice of land.

People use the principles to achieve many outcomes in many climates & soil types. I'm not interested in greening deserts or growing fruit in arid environments.

I want pasture for cattle but I also value some plants (mainly fruits & starchy tubers these days). I'm thinking these rows of productive trees will be positioned reasonably close to my future house. I'm still not sure how I'd integrate cattle into the mix.

I'm just learning & applying some of the theory right now. I don't have pasture yet but I have some time & 2 acres of pretty rugged & largely unproductive land. It's a good opportunity to make mistakes while figuring out what value I can skim from it.