there is a second reason.. Stocking knit want to roll forward.. to the smooth side--
if you want it to turn or fold, a row or 2 (or 3 or 4 rows) of reverse stocking knit will make the 'fabric want to fold the other way..
I use this trick on hats.. to get a sharp fold (from body of hat to crown--when i want a flat (beret like) top! but its good lots of places..
(knit (then felted) bowls will have "flatter" bottoms if you make a turning row/ridge!)