Provide a hook for other view engines from MonoRail, etc
The default URL scheme will look something like this: /<RouteName>/<Action>/<Param1>/<Param2>
MonoRail is more than just the MVC part. I wouldn't be surprised if MonoRail were refactored to take advantage of the ASP.NET MVC HttpHandler just as a means to reduce the codebase a bit.