The Binders returning a stdClass object. This object can not be used to create an Response. Thats why the Dencoder exists. If a bound object should be returned, the encode method can be used:
$stdClass = GetMethodBinder::create(false)->bind($user)->execute()
return new Response(Dencoder::encode($stdClass));
Data that is given by a POST/PUT request has to be converted into data that can be bound to objects:
$data = Dencoder::decode($this->getRequest()->getContent());
$this->container->get('doctrinebinder')
->bind($data)
->to($template)
->execute();