“Sensory” does not mean “visual” alone. The source includes colors and shapes, sounds, fragrances, tastes and tactile properties such as warmth, hardness and softness.
Sight: “red like a rose” — visible color.
Hearing: “clear like a bell” — auditory character.
Smell: “fragrant like musk” — odor.
Taste: “sweet as honey” — flavor.
Touch: “soft as silk” — tactile softness.
These are instructional examples showing that a sensory point of resemblance (وجه شبه حسي) may arise from any of the outward senses. The classification must attend to the specific attribute, not merely the fact that the compared objects are tangible.