Holy water can be used as a grenade.

One might wonder: “If bless is needed to create holy water, but holy water is needed to cast bless, how is there any holy water?” The answer is obvious: the gods can make holy water without needing to cast bless.

Dragon #81 has an article, “Taking the Sting out of Poisons”, which riffs on the DMG glossary entry that says holy water can slow the effects of poison.¹⁾ We do not use that article because it goes too far by making holy water act as slow poison. 25 gp for a spell in a bottle that costs 200 gp per caster level in town. This author's opinion is that the glossary text was either leftovers from a rule that was never refined or published, or the glossary entry meant to say that it slows disease (which it does, in the case of lycanthropy).