WordPress Stylesheet inclusion best practice

functions.php

<?php

if (!is_admin()){
  add_action('init', 'theme_init_stylesheets');
}

/**
 * Registers stylesheets for the current (child) theme
 *
 * @wordpress:action init
 */
function theme_init_stylesheets(){
  wp_enqueue_style('main', get_stylesheet_directory_uri().'style.css', array(), '1.0', 'screen,projection');

  /*
   If you have WP-LESS installed, use the same process with *.less files:
   wp_enqueue_style('main', get_stylesheet_directory_uri().'style.less', array(), '1.0', 'screen,projection');
   */
}