User blog comment:Linathan/Squad Spotlight: Fast Karma Dungeon Farming (Redux)/@comment-28422349-20160718151531/@comment-26140304-20160719023140

Those Mifunes are mainly for auto purposes. It's also considering Mifune has the highest Atk stat in the game so having multiple copies can kill Dilias in just one turn in the fastest way possible. Besides, you wouldn't want to sit through six units using Brave Bursts every stage to waste time.