(acc. to many, k”l is a birchas haro’eh, so lichorah there’s no problem in making yourself unable to be m’kayyeim it)
woops. I got mixed up. They quote R’ Isser Zalman Meltzer as saying it’s a birkas haro’eh but most sources indicate otherwise. (don’t ask me for them; I’m just repeating a shi’ur I heard once, but basically, the mg”a says K”l is a mitzvas aseih shehazman g’rama, so he obviously doesn’t think it’s a birkas haro’eh [which is actually where R’ Meltzer is quoted as having to come to argue] snd a shu”t nodeh bihudah regarding interrupting kri’as m’gillah to be mekadeish the l’vana, so obviously it’s not a birkas haro’eh, or he would’ve just said to not look)