Multiscale provides significant damage reduction, but only when the Pokémon is at full health. Entry hazards like Stealth Rock apply unavoidable chip damage whenever an opponent switches into them, immediately negating Multiscale's protective effect. This forces the opponent to either take full damage from subsequent attacks or spend a turn recovering, creating a window for your offensive threats to secure KOs. This tactical setup also applies to breaking other single-hit defensive layers like Focus Sash or Sturdy abilities, ensuring cleaner sweeps by weakening foes for wallbreakers.