I see what you're saying and yes for the most part the phiosophy is the quickest and most efficient way from point A to point B. When you're training the reason you're doing wall runs etc is practicing this stuff in the event you'll need it for something to traverse. Typically most parkour involves running in a straight line with maybe a few kong jumps or hand vaults.

However flipping and anything aerial is considered extremely inefficient so that tends to fall into the category of "Free Running" some practitioners of Parkour only practice Parkour and are very militant about the uselessness of free running, and the practitioners of Free Running think people who practice Parkour have sticks up their asses. As someone who used to practice Parkour, I can safely say I was just scared shitless of flipping and stuff so I made it seem like it was because of the philosophy of Parkour that I didn't free run. I also found free run to be very show boat-y but Parkour can be as well.