Paladin: Infusion of Light rune and Illumination

What is the point on Infusion of Light refunding the cost of Holy Shock when Illumination, a talent required to even unlock Holy Shock, already does that?

Consider having it refund the cost of Exorcism.

Illumination only refunds heals, infusion refunds attacks now as well.

Still pretty mediocre rune for a 30s cd spell that does pretty average damage, and scales super poorly