Polar Stereographic? It's on the exams in Canada, as is Grid nav. Yes, for helicopters.
Inner workings of instruments? You need to know their limitations so you can get the best information from them.
Appropriate flight levels. Good for performance!
HF radio? They use it there.
Change of Longitude? Handy for calculating lat & long in your head.
Knowledge is knowledge and when you're up against it you need it in your head, not in an exam you skipped ages ago.
Phil