The trouble is that many people use this philosophy of not bringing a compass on to a mountain too seriously. In the UK there have been numerous call outs to the (voluntary) mountain rescue teams to rescue them because the battery in their phone has run dry. The trouble is that redundancy might be apparent, but that doesn't mean it's real.
If you go to a grocery store and take no money, you get no food.
Trouble is, I said nothing about mountaineering, backpacking or even day hiking. I know there are fools who think a smart phone is a tool in the wilderness; those people get what they deserve. Unfortunately, they call us to come rescue them because they are unprepared and don't know what they're doing.
I have zero tolerance for idiots in some backcountry areas using cell phones to call emergency services to deliver water -- and such things happen. However, my comments had nothing to do with this.
The multiple examples I cited to make a case for redundancy are very real, including the compass. You can also probably make a case that after a nuclear war your smart phone won't work, but that old reliable point and shoot camera will. How would that be relevant to this discussion?
There's a useful book I frequently recommend to people:The Art of Clear Thinking
by Rudolf Flesch.