Every time I see these threads...I am reminded of an encounter I had in college. A friend of mine was busying himself learning a slide-rule. I asked him why...he said my calculator could run out of batteries this never will.
True enough, but haven't seen another slide-rule since that day 30 years ago.
Nothing wrong with learning interesting and challenging things. Heck that is why I shoot trad. But arguing that it is necessary or important - not so much.
In the event, I need something besides my GPS, I will take out my compass, pick a good cardinal direction and go.