These are both very useful for self sustain in solo situations, or when the healer actually IS struggling (it happens).

You could just as easily say it's patronising when a Tank blows every single cooldown on one trash pack, or when the Healers Rescues you out of an AoE when you were planning to use your invulnerability.

In addition, they each have their unique uses. Clemency can trigger Divine Veil, and Vercure can be used to proc Dualcast when there's nothing to target.