[xvinci]

In my PPL training you either use the latitude-axis (X) on the equator only, which you will not have in your maps when flying in US or Europe. The alternative is to use the longitude axis (Y) which will always be 1° = 1 NM which can then be readily used in a "what is my groundspeed in knots per hour and what is my ETA" - so to the best of my knowledge you are correct. Then again I am no native speaker.

But it really helps you as in you are able to pick any distance you want to fly on the map and by moving your fingers to the Y axis roughly guess the distance within a few seconds. Even in a very small cockpit and with turbulence. So i absolutely see the need for this with relation to navigation.