A metaphor is "useful" insofar as it creates satisfaction. I speculate that any satisfaction caused by a metaphor is created by a new understanding of predictable applications of events brought about by similar attributes in a sensory comparison. Is this the most common conception of art?
That "understanding" - that is, a higher ability to predict the affects of different events - is more likely to be caused by a direct analysis of the event, as far as I'm concerned. By "direct" I mean a metaphor (symbolic representation) involving as few variables as possible. (aka - "The stove feels 'cold'" or- not what is commonly called a metaphor).
