This will simply make it easier to tell when a Darkfang Mender is about to cast a healing rune, instead of saying the usual "Mending!" battlecry, which they also speak when healing a target directly; thus allowing nearby party members to attempt to interrupt them before they are able to cast it.
...and I know, I could just use poison or curse, but I just find it really annoying how they chant the same line for both actions, and it's hard to tell what they're going to do. (especially if they heal something and then cast a rune under them immediately afterwards.)