Maybe this is an overly simplistic response - but is it possible your question is exploring the difference between "learning something" and being "taught someth

Maybe this is an overly simplistic response - but is it possible your question is exploring the difference between "learning something" and being "taught something"? I suspect that if you truly understand when to apply some technology then you probably have some insight into how it works - the opposite would be that someone has an imaginary table of "when this do that" values prepared by some notional domain expert that they employ. To get back to your issue with interview type situations - I think that there is possibly some confusion between understanding how something works and how then it should be applied - with a lot of people biased towards "how it works in detail" as a key indicator for knowing how to apply. For myself, I find it very difficult to understand the "when" (can I call it) if I do not understand the "what/how" first - but I do understand that might be just me.