Use this card if you control a monster that is unaffected by Spells altogether. "The Legendary Fisherman III" is a good example. He may circumvent effects like "Honest" or "Blackwing - Kalut the Moon Shadow" (these cards shall only deal strict Battle Damage, not destroy the Fisherman) and his effects shall NOT be negated, meaning he will remain indestrucible.
Note that this card's second effect doesn't affect the monsters themselves. Therefore it can be used to assist in destroying the opponent's monster that has low original attack but is unaffected by card effect such as Lyrilusc - Independent Nightingale through battle.