I guess they dropped it as you can align the map north, as opposed to aligning it following the direction of travel.
Out of nothing more than habit, I align my maps to follow my direction of travel. I do though set one of the information cells (time of arrival, distance to via point etc etc) to show my direction of travel as a simple compass heading. For example I see, NE or SW or E displayed. I do this, not because I want to know where north happens to be. Instead I use it as a basic aid, should I go off-route. For example, I know that my route for the day is broadly south east, so I should be seeing SE, E or S in the cell, most of the time. If I see N, NW or NE or indeed W displayed in the cell for an extended period, I’ll know that I am going the wrong way.
It doesn’t take too much of a leap to imagine that if I as seeing S displayed in the cell, then north must be 180 degrees somewhere behind me. If I see E displayed in the cell, then north must be 90 degrees to my left; if I stick my left arm out (as if I was signalling to turn left) then it would be pointing near enough north. Where exactly north (or any other of the cardinal points) is does not interest me too much, most of the time.