The bones of giants, or the bones of dragons? We have always recognised our place in the universe. At least, we used to. We knew we were not alone, and we knew we were small. It's a design feature. Even when there is no god, or what have you, we create these beings and populate our world view with them.
Call it paradoelia. Our tendency to create and see a humanistic universe. Whether the dragon Bones are buried in the mountain or not, the impact of such stories is real, and more important.
Why is it that the volleyball in "Castaway", starring Tom Hanks, resonated so? The most enduring scenes of that movie revolved around Hanks' conversations with Wilson: a volleyball imbued with a soul by the central character to stave off loneliness. That ball was a living character . It was given life by belief. So too, do dragon Bones exist.
A thing doesn't have to be physical to be real.