For accurate navigation we would not use a magnetic compass! We can use Celestial Navigation,
This must be why airline pilots and ship captains use such a method in the present...
I did say that celestial fixes are made to determine an accurate location, even in aircraft, take a look at:
https://timeandnavigation.si.edu/navigating-air/challenges/overcoming-challenges/celestial-navigationLindbergh used celestial fixes, why would he do such a difficult thing while flying solo if it was not necessary!
The magnetic compass along with a ground speed estimate is used to fly the plane or sail the ship, with accurate fixes by other means.
Modern aircraft and ships of course have GPS and other navigation methods available.
Almost all large ships and now many smaller boats use the
Marine Gyro-compass, which finds true north using the earth's rotation. The marine type Gyro-compass cannot be used in aircraft because of their much higher speed.
Yes magnetic compasses are often used for navigation, but they can never accurately give the heading or location!
But you ignore the vital point, on the Bi-Polar map you
seem to fall off the earth circumnavigating along the equator or along latitude lines 0° and then 180°.