"Look, Mikoto, I can see you're really upset about this. I honestly think you ought to sit down calmly, take a stress pill, and think things over."

This is also, somewhat amusingly, game mechanics-accurate, too.
Mikoto is a "piercing"-type character in the game, which do bonus damage against "heavy" armour type.
And basically all Decagrammaton raid bosses are "heavy" armour type, so it wouldn't be out-of-place for you to run Mikoto in a team against such bosses. It's also notable that she's actually decent against Chesed, one of said Decagrammaton bosses.