In order to remove the product long description metabox, simply add the following snippet to your website’s functions.php file:

function remove_pages_editor(){
remove_post_type_support( 'product', 'editor' );
}
add_action( 'init', 'remove_pages_editor' );

Note: This modification to the functions.php file was done in a site using the Divi theme by Elegant Themes. This modification may or may not work using other themes.