The RFID tags can be read if passed near a reader, even if it is covered by the object or not visible.
It can be read hundreds at a time while the bar codes can only be read one at a time using current devices, which reduces the queueing time.
Preventing unauthorized access to restricted areas.
The RFID-based control system allows the event organizers to more closely regulate numbers and makes the event safer.
Collecting the information of RFID wristband holders, including their locations and how long they've been staying in the specific allowed areas, to figure out what stuff they might be interested in and arrange the next event accordingly.