“The face is like the moon in radiance.”
“Her voice is as soft as the rustle of the breeze.”
“Silk resembles smooth skin in softness.”
The respective aspects are radiance, quiet sound, and softness. Each can be perceived through a relevant sense. The simile does not need to invent a new composite image in order for the quality to be present in both terms.
Actual participation does not imply equal intensity. The radiance of a face and the moon may differ enormously, yet a resemblance may be asserted in the selected feature. Simile draws attention to that feature rather than establishing identity of all qualities.