Karador and Life Light Spell?

[Helios]

It just occurred to me that the Life Light spell might be pretty good for the battle against Karador (I assume this is why the Tree of Life Sprout quest gives you the spell right outside his castle). Is it actually useful in practice? I'll give it a shot in my game this time around, but I just started. Has anyone had any success using the spell in that battle?

Edit: If it only makes undead units run away one hex, then it's probably better to spend the mana elsewhere. I didn't realize it only made them run one hex.