It is also a fact that children delight in such stories. The question is whether the reading will entice children into the occult, and prepare them to adopt gnostic and new-age models of religion?
Perhaps we should begin with the way God has made us in his image. As distinct from the other animals, we are designed to be able to look at and evaluate alternative models. We can do this with scientific theories (flat-earth v. global, Newton v. Einstein), and alternative kinds of medicine (in India you choose between Ayurvedic, Yunani, Homeopathic, Acupuncture, Western, Holistic. etc.). And all over the world the human animal looks at, discusses, and chooses among the various religions and ideologies that we encounter in our culture.
There seems no evidence that looking at alternative options in any way hinders Christian faith. The Messiah arranged for his church to be born, survive, and triumph, in an incredible confusion of alternatives. A mature Christian is someone who has engaged with other alternative options and chosen to go with Trinitarian Theism.
What is needed is that children learn our Christian model of creative
love in comparison with other religions and ideologies where the love of
God is not in view. If they have a heart for love, they can be trusted
to see the difference and choose the right direction. And it seems to me
that reading a fantasy story followed by a Bible story is a good way to
help them do that.