IOS and macOS Accessibility Switch Control requires Bluetooth pairing. Another useful feature would enable this board to behave as an HID Bluetooth Keyboard or Mouse. Both would be extremely helpful to those wishing to develop hardware interfaces for the disabled.
Please can anyone give some indication when the ArduinoBLE library is likely to include this important functionality?
I don't have any information for you on when, but I can tell you that the Arduino developers are aware that the community wants this functionality and are planning to add it to the library. You can get more information here:
Subscribe to that issue thread to be notified of progress on this subject.
You could develop a HID over GATT application yourself with the BLE library as is. I do not believe this would be too complicated for someone who understands the USB HID side of things. If you know a good source of how the HID report map stuff works, I could see if I can get this to work.
I'm pretty sure bonding/pairing must be implemented first.
There are projects using other Arduino compatible BLE boards for folks with limited mobility.