Defeat

The power-2-or-less clause is doing all the work here, and it is a deliberately narrow window. This is removal built to police the bottom of the curve: mana dorks, early aggressors, the two-power beaters that fill out an opening. What it cannot touch is the thing you most want dead by the midgame, the four- and five-power threats that actually end games. Black has a long tradition of removal that pays for cheapness with a restriction, whether that restriction is a converted-mana ceiling, a nonblack target, or a downside attached to the caster; this one buys hard destruction at two mana by simply refusing to look at anything sizable. The trade is honest: unconditional kill (no regeneration clause, no exile-versus-destroy wrinkle to navigate), but only on a creature small enough that you were probably winning the exchange anyway. Sorcery speed compounds the narrowness, since you cannot hold it up to ambush a freshly cast dork or punish a combat trick that pumps a creature out of range. Its worth swings entirely on how low the relevant power level of a format runs: when small creatures carry the game, it is a clean answer; when they do not, it destroys nothing you needed destroyed.