While I don't play Bard, I will also note that while Foes is mainly to boost caster DPS, it also increases the damage of Ninja's Ninjutsu skills, and a few of Dark Knight's attacks. Not necessarily worth draining your MP over in most situations, but if your party is just barely missing a DPS check, it could help get that extra bit of damage in that you need. Regardless of whether you ever find use for this knowledge, it doesn't hurt to know it.....