>>537111960 Atk Aipom Double Hit (2 hits) vs. 0 HP / 0 Def Abomasnow: 72-86 (22.4 - 26.7%) -- approx. 15.6% chance to 4HKO
0 Atk Aipom Dizzy Punch vs. 0 HP / 0 Def Abomasnow: 72-85 (22.4 - 26.4%) -- 16.9% chance to 4HKO
Ignoring accuracy, multi hit moves like double hit are slightly better damage-wise because of damage rolls being more favorable. No bonus stab, but they can potentially cause secondary effects like flinched more. Though things like iron barbs or rocky helmet make it more equal