I experienced a strange bug. When I purged one of my cities, it would give me a large sum of money, about 3000-5000 gold. Haven't messed with the Inquisitors much, but I'm guessing that isn't supposed to happen.
I haven't created this mod. But the code says that it is intented! You get money for removed buildings, the removed religion itself and you will get a bonus for a remove of a holy city. And as it seems this may result in about 3000-5000 gold. No bug here. But maybe it is not well balanced. I have no experience with this feature.