No thats not the case. You still have to use S3 as the origin. This is talking about allowing you to assign a default root document, e.g. a index.html so that

No thats not the case. You still have to use S3 as the origin. This is talking about allowing you to assign a default root document, e.g. a index.html so that requests to (e.g.) http://cache.mydomain.com/ http://cache.mydomain.com/ will return something.