Chance to cast divine bolt on 0 cost skill

Does anyone know if the “+6% chance to cast divine bolt when you use a 0 cost skill” can proc on indirect spell cast such as Smite from Palarus’s Sacred Light and the Warpath’s Winds of Justice node?

The phrasing “when you use a skill” implies you’re actually using a skill, not having it proc by something.
So it can only proc on skills you use yourself, but on not any kinds of indirect castings.