>>35263661Shedinja is one of those mons that is utter shit in regular play but has the ability to be completely game-breaking in specific situations. Random battles? if you save it long enough and show it at the right time, your opponent might literally just ragequit. Ubers? kyogre can't touch it. Hackmons? welcome to the world of infinite sturdy. Literally everywhere else with weather/hazards? shit.
Even in game I think NPCs don't run it because it could be unfair against kids that don't know about what it does.