When I try to find where fish would be I think of the "Three C's"

Current, Cover, Cuisine.

I know a fish will want to find a place where they aren't burning calories just fighting the current. They're going to look for a place with cover from predators. And they're going to find a place where the food source is flowing towards them.

However, I just read in a book about fly fishing the high Sierra mountains that a plunge pool is a good spot to fish. To me that seems to violate the "Current" part because the fish would have to fight the very strong pounding current of the falling water.

Therefore:

1) What have your experiences been with fishing a plunge pool? For the sake of argument let's say a plunge pool is the pool below a waterfall around 2 to 6 feet high.

2) If they are good spots to fish then why does that work? Why aren't the fish trying to avoid that current?

3) If it is a good spot to fish, what would you use? I would expect nymphs because the bubbles and foam would obscure a dry fly on the surface. Also, just about anything would be pulled down into the foam anyway.

Thank you for any advice and wisdom you can share on this topic.