Metaphors enrich language; just think, would you rather listen to a singer with a "silky voice" or just a "pleasant voice"? In evoking the smooth feeling of silk, the phrase associates a physical texture with something that has none.
Here's a very quick article with a very important message: metaphors that we use in our biz stories actually help listeners feel what we are sharing about.
Wow! This goes hand-in-hand with a recent article I scooped on change that talks about when listeners hear stories they are not only seeing pictures, they are simulating the experience.
This article also talks about the neuroscience of a powerful storytelling device: metaphor.