Beacons are becoming fixtures at major events. Several events have been using them successfully for years. They can be used to help internal staff communication, facilitate networking, indoor mapping, collecting data, sending marketing messages, etc. Beacons help apps engage its users. So for events, where people use the event app very heavily for a short period of time, they can add a lot of value.
More information: http://www.ibeacontrends.com/4-beacons-events/