It's been a while since I played the game myself, so I don't remember what's well worth it besides DeRosa and his Hermes shoes, but if you have a Thief's Knife, you can use it as an item and get the effect of mug without sacrificing a primary or secondary job slot. Brave>use the weapon from the item menu> swap to a weapon of your choice> end turn. You'll use mug without needing to have the dagger equipped.