So far, Cloudfront's origin servers were hardcoded to be your S3 bucket. So if you used Amazon as an extra service to serve static files of your website from a CDN, you'd have to do trickery to set up your website as the S3 bucket's origin. I assume this is what he was talking about, not having to copy his file to S3 so the CDN edge location can pull it from S3.
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/ will return something.