Perhaps if they are unaware that a 3D image of a geoid projected onto a 2D plane can cause issues, however every projection will have its own failings whether area, shape or directional (angular). Familiarity also comes into play, and i believe that is more at the root of the issue you bring up.

As for your navigational questions, this Reddit thread may be helpful https://www.reddit.com/r/explainlikeimfive/comments/4s4869/eli5_how_mercator_projections_are_better_for/

Mercator wasn’t created in order to increase importance of the northern hemisphere, but to allow for directional rhumb lines to be drawn for shipping. For its intended purpose of navigation, it does an excellent job.