Let me start right off by saying, this spell is not NEEDED. However, now that they broke the mold in the Arcanum, why not add this spell? When I say they broke the mold, I'm talking about the Gobbler spell for Myth school. It can't be learned any place else but the Arcanum, even though it's a Rank 3 spell. So, why not add Life Bat to Zander's offerings? Keep in mind that Gobbler isn't needed either; it's more of a "kitchy" spell.
Honestly only reason why Gobbler was added... You can already obtain Myth trap, so they had to fill it in, with another majority weak spell... Life link... Trench... Precision...etc... Myth the only other weak spells, would be minions... Unless there's a 2-4 pip spell I don't know about.... And so KI just goofed it up and tossed a whole new spell Gobbler
The logic doesn't fit though. You can learn Firetrap from Dalia, Life Trap from Mildred Farseer, Myth Trap from Cyrus, and Storm Trap from Halston. It's bizarre that Myth can't learn Gobbler in WC, and instead can only learn it from the Arcanum. Lifebat would be a neat spell to be able to learn, even if only rarely useful, like Gobbler is.