Why using the "use function" import statements for PHP native functions?

Hi. I am strugling to understand, why to use "use function" import statement for PHP native functions. An example code:

PHP Code:

<?php

namespace Acme\Package;

use Acme\Package\SomePackage;

// why this?
use function md5;
use function json_encode;

class AnotherPackage {
    // some code with using of a md5 and json_encode functions
} 


Can you write me, why to import the PHP native functions? I have no idea and could not find an answer.