We use fire as a metaphor for many things—love, faith, energy... That astonishing force of nature has been an indispensable part of human life from the beginning. The passion to create is a similar force of nature. Creativity, like fire, can be a spark or a raging inferno and the two forces may join to fashion a powerful beauty.
The words heat and flame are used in so many ways...especially in slang. In art, heat can be captured in various ways. "Flame" is difficult in both technique and emotions, and still be a work of art.
I've seen christian writers uses the pan taking on the heat of the flame as an analogy for sanctification and divinization, likely drawing on the burning bush image and Zoroastrians speak of eternal fire as the highest self.