title: Reason to return promise from another promise?
body: <p>In the following code, what would be the reason to return another promise from the <code>success</code> or <code>err</code> method? As you can see, <code>someFunction</code> already returns a promise and we could easily return that to the caller. </p>
  
  <p>I don't understand the reason to make another promise while we are not decorating/manipulating the response or the error. Is there a use case that I'm not aware of?</p>
  
  <pre><code>function() {
      var p = $q.defer();
  
      someModule.someFunction(input)
      .then(
        function(success) {
          return p.resolve(success);
        },
  
        function(err) {
          return p.reject(err)
        }
      );
  
    return p.promise;
  };
  </code></pre>