That part about Bob Larson may tell you all you need to know about the power you wield as an exorcist. But is that the power you wanted when you decided to go into this business? Money from scared people? Poorly-produced videos? A website any 9-year-old could create?
When an exorcist performs his duties and performs them well, the power he and his possessed hosts feel is the power to cast out one of the most powerful things known to mankind: Devils and their ilk. You are performing the work of God; you are placing God inside a person or place where He has previously been cast out.
If that isn't all-powerful…what is? (And no, failed attempts at converting Satanists to Christianity on live TV don't count as powerful.)