I have the 5.3 which also has this. On my camera it lets you connect to the iPhone directly from io.Share without first going to Settings and selecting the Wi-Fi access point. I’m not aware of any other changes from this.
Yes, as bassman reports, the Bluetooth is just to be an always on service to switch on the wiFi connection between the camera and oiShare or Capture. It is not a standalone service like we're used to between phones etc.