See the paragraph above that
The safe and recommended method of adding JavaScript to a WordPress generated page, and WordPress Theme or Plugin, is by using wp_enqueue_script(). This function includes the script if it hasn’t already been included, and safely handles dependencies.
While you can include JavaScript the other way it is not recommended. The main reason for this is because your script might depend on the ACF scripts being loaded first. This dependency can be handled by WP and it will make sure the scripts are loaded in the correct order by telling it what other scripts your script depends on https://developer.wordpress.org/reference/functions/wp_enqueue_script/. In most cases when extending ACF with custom JS you’d want to use $deps = array('acf-field-group');
