Writers use figures of speech because they turn abstract feelings into scenes readers can picture, so emotion lands vividly.
Instead of she felt grief, a writer shows a folded umbrella drying in the empty hallway, so the sadness is witnessed through detail.
A figure of speech also has a real limit: it works only because the reader shares it. The folded umbrella in the empty hallway carries sadness because the reader knows what a folded umbrella is, what an empty hallway looks like, and what it can suggest about absence. The picture happens in the reader's mind, so the writer can only build with materials the reader already has. An unfamiliar image gives the reader nothing to picture, so instead of sharpening the feeling it muddies it, leaving the reader decoding rather than feeling. A worn-out image fails differently: the reader pictures it instantly but has stopped reacting to it, because phrases seen a thousand times slide past without stirring anything. In both cases the image obscures meaning rather than sharpening it, because the shared picture that makes figures of speech work is missing or faded.
Take a hesitation before a hard choice. That hesitation is abstract: nobody can see or touch it. Because writers want readers to feel it, they give it a physical shape instead of just naming it.
So the writer turns the hesitation into the word hung in the air like a coin tossed and still spinning. Now the reader watches the moment, waits with it, and feels the suspense of not knowing which side will land.
Notice what the image does that the plain label cannot. He hesitated states a fact, so the reader registers it and moves on. The spinning coin makes the reader hold the uncertainty in midair, so the same idea arrives as an experience rather than information.
The mechanism works because our minds borrow sensory experience to understand abstract things, so a tangible image gives the reader something concrete to react to. The coin does not replace the hesitation, it carries the hesitation into the reader's imagination, where suspense becomes something felt rather than reported.
One limit worth naming: this mechanism works in doses. Because each figure asks the reader to stop and picture something, stacking several in one sentence can tire that attention, so the images blur together and the message gets harder to follow rather than easier.
Picture the coin example again. If the same paragraph also spins a wheel, tilts a scale, and cracks a mirror, the reader juggles four mental pictures at once, so the original hesitation loses its focus instead of gaining vividness.
There is no fixed cutoff to point to. A dense passage may feel rich to one reader and cluttered to another, so the same sentence can sharpen an idea for one person and bury it for the next.
So the causal answer stands, but with an edge: figures of speech make abstract ideas concrete because the mind borrows sensory experience, yet that same concreteness becomes noise when too many images compete for the reader's single attention.