[DF] Holy water seems to have no purpose

[Bruno]

So far, I haven't found a single DF monster with a Weakness, Revulsion, Vulnerability, or Dread of Holy water, despite its description in the DF 1 equipment list as that being it's only use. Demons and undead in GURPS Magic and GURPS Fantasy are conspicuously missing these traits as well.

So, some questions for the audience:

What classes of monster would you assign these sorts of traits to? All Truely Evil creatures? Undead only, regardless of Evilness? Demons only, same footnote? Different degrees or combinations of traits based on creature type?

I'm thinking of Weaknesses for Undead, and perhaps Revulsion or Dread for demons.

What other uses can you think of for holy water and related substances (holy oils, incense, etc)?
I can see sprinking one "charge" of holy water per hex being good for a +1 to rolls to exorcise a cursed area or reconsecrate a dark altar. If not per hex, then perhaps per yard radius.
It also seems appropriate for area spells of protection - same idea, one bottle per hex.

It's too cheap for Holy characters to use it at a one-bottle per spell benefit unless it's a really trivial benefit - one FP off on the spell makes it 3x the cost of one point of Power Item, but doesn't require a power item of great value to have 20 of them. And the Holy character can get them half price (as per DF2) in town anyways. I would say one per spell, and only on ceremonial castings perhaps.

Any other ideas?