If you have a simple application, then, yes, it's not going to give you a whole lot of new information. However, even in the basic case, you do get the HTTP response headers. That can be helpful sometimes in debugging problems.

The other reason why this is useful is that in larger complex deployments, there may be requests that get throttled, dropped on the floor, etc. as an automatic means of shedding load. We have such a mechanism at StyleFeeder, because we have so much robot traffic. Other times, load balancers and the like will inject stuff into the HTTP request stream in a way that isn't obvious when you're working in a dev environment.