Why should I use IHttpActionResult instead of HttpResponseMessage?

Question

I have been developing with WebApi and have moved on to WebApi2 where Microsoft has introduced a new IHttpActionResult Interface that seems to recommended to be used over returning a HttpResponseMessage. I am confused on the advantages of this new Interface. It seems to mainly just provide a SLIGHTLY easier way to create a HttpResponseMessage.

I would make the argument that this is "abstraction for the sake of abstraction". Am I missing something? What is the real world advantages I get from using this new Interface besides maybe saving a line of code?

Old way (WebApi):

public HttpResponseMessage Delete(int id)
{
    var status = _Repository.DeleteCustomer(id);
    if (status)
    {
        return new HttpResponseMessage(HttpStatusCode.OK);
    }
    else
    {
        throw new HttpResponseException(HttpStatusCode.NotFound);
    }
}

New Way (WebApi2):

public IHttpActionResult Delete(int id)
{
    var status = _Repository.DeleteCustomer(id);
    if (status)
    {
        //return new HttpResponseMessage(HttpStatusCode.OK);
        return Ok();
    }
    else
    {
        //throw new HttpResponseException(HttpStatusCode.NotFound);
        return NotFound();
    }
}

Answer 1

You might decide not to use IHttpActionResult because your existing code builds a HttpResponseMessage that doesn't fit one of the canned responses. You can however adapt HttpResponseMessage to IHttpActionResult using the canned response of ResponseMessage. It took me a while to figure this out, so I wanted to post it showing that you don't necesarily have to choose one or the other:

public IHttpActionResult SomeAction()
{
   IHttpActionResult response;
   //we want a 303 with the ability to set location
   HttpResponseMessage responseMsg = new HttpResponseMessage(HttpStatusCode.RedirectMethod);
   responseMsg.Headers.Location = new Uri("http://customLocation.blah");
   response = ResponseMessage(responseMsg);
   return response;
}

Note, ResponseMessage is a method of the base class ApiController that your controller should inherit from.