Child was reading and loving a rendition of Beowulf and was curious about monsters and dragons. My attempt at explanation: before we had cameras and airplanes and internet, it was reasonable to believe that monsters and magic and dragons existed.

Like how we tell stories about aliens. Our descendants will explain to their little ones how 21st century people lacked faster-than-light and nanotechnology and synthetic cognizance so they could entertain weird ideas about alien life.