>>47726601Objectively? Stall is a playstyle that tries to force bad plays from your opponent. Through longevity you will be racking up passive damage to your opponent while healing from both passive and active damage. Stall works best when the opponent isn't packing wallbreakers or 101 hp sub mons. Or when the opponent misplays a lot. It's a winning strategy when the meta isn't offensive enough, or when most of the offensive mons are setup mons like in Gen 6.
You will see more stall in tournaments and high ladder because it's a style that is pretty hard to mess up once you get the gist of it. Impatience and misplays are rarer but will always be exploitable.
Stall is good when good wallbreakers aren't flexible. Back in gen 5 OU, when genesect was legal, you wouldn't see much stall. Because it would have to face both weather teams and Genesects. Back in pre DLC and IoA meta stall wasn't good because Kyurem is too flexible. Freeze-Dry Kyurem is a monster that didn't exist before. And it pretty much eats stall for breakfast.
The real answer: It makes people go malding after turn 50. Having people be angry at you is better than winning most of the time.