It seems to me, after seeing “The Conjuring” and subsequently reading the book The Demonologist," that the Warrens were using their gifts strictly to help those who were suffering from diabolical attacks. From what they relate in the book, there were many people experiencing “hauntings” and they tried to use their knowledge and gifts to discern the ultimate cause of the trouble, educate the afflicted party, and, if necessary, possible, and permitted by the Church, help eliminate the demonic source of the problem.
It doesn’t seem that this is the same thing as “using a medium” because they were (at least ostensibly), using their own gifts to do God’s will in fighting the forces of evil. It would be another matter if they were sitting at home conjuring up demons or spirits to tell them where they could get their next paycheck.
I do admit that some of the stories I’ve read seem to indicate that the Warrens were frauds, and I’m curious if anyone within the Magisterium can confirm or deny their legitimacy.
I’d also like to hear some official Catholic Answers response to the claims of Ed and Lorraine Warren.