Cold and poison is the resists that no one raise using refinement on armor,
for a bok mage fighting without a necro cold is as good as poison damage.
cold damage is also the only damage type you can raise on a wooden wep using enhancing, which can bring that wep up to 100 cold damage.
Fire ball on a wep is nice because it is a delay between the hit and the spell hits, which raise the chance to disturb enemy casting.
The combo you want on a wep 70 elemental damage/ 70 hit spell can take up to 30k tunic uses