Ya know, it makes me wonder. Since we all know that supernatural stuff isn't real, these wandering priestess and exorcists from centuries ago were really just con artists—selling nonsense and performing fake rituals for money or trade goods.
It was a whole industry perpetuated by superstition and tradition. These poor villagers and peasants who lived hundreds of years ago, barely surviving at the time, gave up precious resources for nothing. =/
People have always tried to avert calamity like illness, famine, and natural disasters, and cultivate the good in life like healthy childbirths and bountiful crops. In the past, they'd try to tap into supernatural forces or contact powerful spiritual beings to do what we usually do with science now.
Contacting a priest or an exorcist or the like in that context is no different from you going to see a doctor. Doctors devote their time to developing an expertise with human health so they can focus their knowledge and help people who can't afford to do the same. Priests and exorcists are the same, just in terms of the spiritual and the occult. That's how people in ancient times would likely see it if you really asked them to think about it.
I personally believe there is a spiritual dimension to life, but you can't bet it all on belief. When you place everything on what you believe and not what you know, you can get taken advantage of or fail to really understand your own circumstances. Then again, none of us really know all that much. Sometimes you have to put faith in things that are outside of your control, whether it's gods, the forces of nature, or other people.