User blog comment:Alcahona1095/High School DxD BorN Episode 11 Review/@comment-195.189.88.79-20150614082626/@comment-26209278-20150614090404

What Striker said seems logical.

Also, this is a harem anime. They gotta put fanservice in where they can. Sure, the armour wouldn't make sense in real life, but it fits for the theme. Look at computer games, they always have fanserviced armour on female characters. There's a reason. It attracts a larger demographic.