Don't know about the rest of the games, but in V and VII I used Blue magic/Enemy skill primarily as an off heal/buff class that had options to lay down the damage. Most of the attacks are increasingly useless in the games, supplanted by better ones. The heals and buffs are always useful.

I'd make Blue a Healer, but I'm aware that this is mostly due to my own experience with the class.

Also: Berets, Capes and Masks, all the way.