Spring MVC still works with JSPs and in its core it provides nothing more than a simple dispatcher servlet that uses the mechanisms provided by the Spring MVC framework (where you register your controllers in etc.). I would say it is about convenience and making things a lot easier to write and maintain. Additionally you can react more easily to current developments (e.g. RESTful services... you would have to code all of it by hand in a servlet). In the end that is what frameworks are for.
