Earlier quoted context omitted.
Are you talking about this? you left out a word. Simply point to your data in Amazon S3
Still makes no sense. Please explain if you understand.
To me the obvious use case is querying your log files as stored on s3. Query for a specific combination of features, or do some (simple) processing on them.
It's really only useful for a small list of file formats. Doesn't really do much for you if you primarily use s3 for binary data or static web hosting.