You need to be wearing
light armour as well as holding your cleric rod for those passives to work.
They are important in party play. They apply to the person you buff - we tested it. Gives them extra Str, Int, defense... explained in the skill description.
But if you're just soloing, don't plan to play cleric in a party, and are wearing robes, the passives are a waste of sp.

(And I'm guessing if you aren't going to party as a cleric, you probably won't be jobbing as a cleric, either.)