Having people in the party who can manipulate thaumic particles into water is really helpful. Especially if you’re accustomed to bathing every day. (It does not work with complex things like food, though. Water is easy. It’s two elements. But summoning, say, a bacon sandwich would require so many components, it could take years of trial and error, memorizing complex strains of amino acids, etc, it just isn’t worth the bother.)
It’s a good thing for Niki that, like Taurs, Elves are communal bathers. There’s only so far a Centaur can reach with a scrub brush.