>>57061455this
they have zero place in casual play (because the campaign's difficulty doesn't have anywhere close to tight enough tolerances for IVs to actually matter, and since barely any opposing trainers have EVs you'll always have higher stats than the enemy assuming equal levels due to EVs) and in competitive play (because they add an unnecessary barrier to entry that shouldn't exist in any competitive scene, period; see picrel)
also they spit in the face of one of the franchise's intended messages that you can overcome everything if your bond with your pokemon is strong enough, despite the fact that your mons will be mechanically inferior without perfect IVs
and I swear to god if someone implies "they make mons more unique" yeah uniquely worse if you try to bring them into battle against players with mons with full IVs, and there's ways to make mons unique from each other without randomly making some worse than others with no way to change them; there's natures, abilities, EV spreads, moves, pokeballs, shininess, nicknames, held items, and possibly more depending on generation
>but muh bottlecapsunnecessary halfassed solution to a problem that could have been easily removed in the first place
the only justification for IVs was hidden power but that got removed with gen 8 five years ago
EVs are fine for both gameplay and story purposes as they're reassignable via berries (in gens 4+) and represent your mons getting stronger after constantly fighting by your side
