Add justification

README.md

@@ -10,6 +10,13 @@ that makes it easy to turn any mailing into a job for running later. That's
 one of the most common jobs in a modern web application: Sending emails outside
 of the request-response cycle, so the user doesn't have to wait on it.
 
+The main point is to ensure that all Rails apps will have a job infrastructure
+in place, even if it's in the form of an "immediate runner". We can then have
+framework features and other gems build on top of that, without having to worry
+about API differences between Delayed Job and Resque. Picking your queuing 
+backend becomes more of an operational concern, then. And you'll be able to
+switch between them without having to rewrite your jobs.
+
 
 ## Usage