Spare Micaiah for Distant Defense?

So....after spending 100+ orbs to get Micaiah on her banner, I just got a second one with my free Valentine's summon (same nature, +atk -res). I'm not too sure about her merge potential, but she has distant defense 3 which is a REALLY useful skill to have. I'm just torn on who to give it to.

My first option would be my NY Corrin, who I'm building to be a ranged tank. His current build:

Guard Bow+
Swap
Ignis
Fortress Def 3
Quick Riposte 2 (don't have 3 yet)
Threaten Def 3

I gave him Fortress Defense since I didn't have Distant Defense 3 at the time, but is it really that much better that it's worth sacrificing a Micaiah for? Granted the defense bonus is slightly better, he'll have more attack plus it will patch up his bad resistance against mages too. And I suppose seeing as he doesn't have Close Counter there's no point in the added defense against melee units, since he won't counter them anyway.

I don't really have any other contenders for this skill, but I'm torn between using it on NY Corrin or just waiting till another unit comes along who can use it better.

Thoughts?