under maintenance

I found this solution , in view i create a specific view ( under_maintenance.php)  directly under view  . 
In home or other controller create a function:

Code:

public function under_maintenance()
    {
        return view('under_maintenance');

    }

in route

Code:

<?php
namespace Config;

// Create a new instance of our RouteCollection class.
$routes = Services::routes();

// Load the system's routing file first, so that the app and ENVIRONMENT
// can override as needed.
if (is_file(SYSTEMPATH . 'Config/Routes.php')) {
    require SYSTEMPATH . 'Config/Routes.php';
}

//variabile in manutenzione
$under_maintenance = 1;



/*
* --------------------------------------------------------------------
* Router Setup
* --------------------------------------------------------------------
*/
$routes->setDefaultNamespace('App\Controllers');
$routes->setDefaultController('User');
$routes->setDefaultMethod('index');
$routes->setTranslateURIDashes(false);
$routes->set404Override();


//route under maintenance
if($under_maintenance){

$routes->get('(:any)', 'Home::under_maintenance');

}else{   

//all other roules
}

there could be problems using this way?