Please do have a look at django-rest-framework, I just stepped over from tastypie to this new framework, works great!
http://django-rest-framework.org/
Especially the class based views and the browsable api! and may other advantages (e..g. to upload images)
And to answer your question:
The rest-base service is an extra entry to your webapp.
I made some api's for some projects using the django-rest-framework, most project members were surprised they got a webapp as an extra, while it was actually the other way around. You make a django app (with views models and urls) and on top off that you make the api.