Already knowing what the terms flank and rear meant helped a lot when restarting mnk in 2.0 (positionals were what drew me to pgl back in 1.0) but I also didn't notice the break in the target circle at the back until a couple weeks in. I just went fully to the side or fully to the back based on the enemy model. Knowing the exact measure for each position allows you to get the same effect but with less time spent moving

They could mention it in one of the pop-ups that appear for new chars since all the melee have to use positionals eventually