Worst unit huh......
IDK if this worst or not
But personally I don't find it to be usefull for My currently Team on DMM

Thief....
Increase items drop rate but at the price of Enemy + 20% ATK and HP (IIRC)
And it seems will increase droprate at AW and also increase Enemies stat too
Their stat is also low...

But I do saw people using them just to test their strenght to kill Mithril Golem and any hard boss
Gee.....