This solution makes FTP/SFTP(SSH) communication with your SAP Backend system obsolete. Your ABAP programs can still use file-based integration (Import/Export), but the communication with PI/PO is done with HTTP(S). This is especially useful, when you do not want ANY system to connect to the file system of your SAP landscape or you want to make sure only the SAP system itself is accessing the (local/remote) file system, no other system or user.
The integration is done through the ABAP Proxy runtime, which supports multipart messages. The XML data of each ABAP proxy contains the meta data (file name, directory, job/program name) and the data file itself is transferred as an attachment.