I was speaking to someone who said that they believe a woman's hair is seductive and should be covered for modesty, besides for her husband. So she wears a wig to cover up her real hair. I didn't get how a wig is any different. Do you?
This sounds like a caveat of Islam, where women wear Burkas. It is much of the same reasoning. Hair is seen as seductive and for your husband only, hence the head covering. The only difference, is that in Islam, the head covering is a scarf, not a wig.
I suppose that, if they think that their hair has magical powers and if they are conscious about such , they would want to conceal their powers in order to not abuse them. What better way to conceal ones hair than with a wig? The onlookers only see a person without a hat/scarf on their head and not the mystical hair that lays beneath the wig. With just a hat or scarf some of the hair would likely be seen.