In this sample an RFID tag is scanned by the RFID reader and a scan event is sent to the BizTalk RFID gateway. At the end of the gateway pipeline the event is published to BizTalk. In BizTalk some transformation and integration with the line of business system occurs and BizTalk is able to update the line of business application with an event such as a product leaving the warehouse.
In this sample BizTalk RFID adds value in the decoupling of RFID scanners so that many different types of scanner can plug into the RFID gateway and then the gateway has its processing pipeline where you can implement some basic logic such as de-duplication or checking of stuff related to events.
When the more complex integration with other systems is required then the event can be passed off to BizTalk Server which specializes in this systems integration area. In BizTalk you can do something simple like map and forward data to a single application or something much more complex like orchestrate updates across multiple systems.