Idioms are commonly used styles, guidelines and patterns largely agreed upon by a community. Writing idiomatic code allows other developers to understand better what is happening.
After all, the computer only cares about the machine code that is generated by the compiler. Instead, the source code is mainly beneficial to the developer. So, since we have this abstraction layer, why not make it more readable?
Remember the KISS principle: "Keep It Simple, Stupid". It claims that "most systems work best if they are kept simple rather than made complicated; therefore, simplicity should be a key goal in design, and unnecessary complexity should be avoided".
Code is there for humans, not computers, to understand.