Bluetooth Pairing with iPhone

Can someone from Anova explain how Bluetooth Pairing works with the with iPhone?

Why do you need to use the app to pair the APC?
Why isn’t is visible under the Bluetooth settings?
Why does it seems to re-pair every time you start the app or the APC?

What have you done differently that means pairing (and thus any kind of diagnostics) can only be done through the app?