The run, in concept , isn't entirely crazy - mind games with the keeper, building anticipation with run up and give enough time to create indecision in the keeper, maybe edge him to commiting a bit early to one side.
But now that hypothesis has been tested and is actually an awful technique. The run up seems to throw Pogba himself off more than the keeper. Similar ideas, like the stutter step are much more effective in getting the gk to inch one way early. And the final steps seem (to me) like they don't facilitate a proper strike of the ball nor ease in diversity of the placement .
Basically, forget that it looks silly, more importantly it's actually an awful way to take a penalty. And of course Pogba would continue to use it without changing all the way since his youth days. Seems just about right for his level of stubbornness/arrogance.