Attack IVs aren't bad on physical attackers, as they need them for maximum damage output. On any Pokémon that isn't a physical attacker (special attackers, walls, etc), 0 Attack IVs are good for two reasons: Foul Play and confusion. As both go off the Attack stat of the targeted Pokémon, the fewer Attack IVs a Pokémon has, the less damage they can do.
Special Attack IVs are completely useless to worry about; you just want 31 at all times except in a few very niche scenarios that aren't viable competitively.
Hope I helped!