Still works fine for me. Make sure you change 'post' to 'page' if you are wanting it to work on your pages.
If you need it for both posts and pages, then use this.
// Remove the editor. Change 'post' to your custom post type.
add_action( 'init', function () {
remove_post_type_support( 'post', 'editor' );
remove_post_type_support( 'page', 'editor' );
} );