Someone please correct me if I'm wrong, but my understanding is in Rails you still need to define every action in the controller. With DRF, you just inherit from a ModelViewSet, declare the queryset and serializer on the class (or have methods return them if you need custom behavior), and you're good to go. It makes prototyping so much easier, and adding filters and permissions is very straightforward.
Maybe the DRF for Ruby is grape https://github.com/ruby-grape/grape/blob/master/README.md but I never used it. I just fill in the standard scaffolded REST methods in the controllers with queries and write json views (Rails and Django have different terms and concepts, MVC vs MVT.)
