What does an idiomatic expressions convey?

Answer 1

It conveys different meaning than The Literal translation (word-by-word).

"People use idioms to make their language richer and more colorful and to convey subtle shades of meaning or intention. Idioms are used often to replace a literal word or expression, and many times the idiom better describes the full nuance of meaning. Idioms and idiomatic expressions can be more precise than the literal words, often using fewer words but saying more. For example, the expression it runs in the family is shorter and more succinct than saying that a physical or personality trait 'is fairly common throughout one's extended family and over a number of generations."

Answer 2

An idiomatic expression conveys a figurative meaning that is understood by native speakers of a language, but may not be interpreted literally. These expressions add color and cultural context to communication, often conveying a message more vividly or succinctly than literal language.