I just use heal branch cleric robe medic pouch med ring for healing
Arch bishop is +20% (since not a bishop) and +15% matk I think that 30% heal over all does better but I could be wrong. I think if you don't want to equip swap when fighting arch bishop may be better since heal staff matk damage is lowered.
It would be a cheaper option if that was your only weapon. If you want better light damage then catrina would be much better 20% matk and light magic up by level. heal branch also gives -1 second skill delay which helps when buffing.