Comment by rustyhancock

It's because they are heurists intended to be applied by knowledgeable and experienced humans.

It can be quite hard to explain when a student asks why you did something a particular way. The truthful answer is that it felt like the right way to go about it.

With some thought you can explain it partly - really justify the decision subconsciously made.

If they're asking about a conscious decision that's rarely much more helpful that you having to say that's what the regulations, or guidelines say.

Where they really learn is seeing those edge cases and gray areas