The ComPilot is a Bluetooth and direct audio input receiver for your hearing aids. You can pair Bluetooth devices to it which are then relayed to your hearing aids by the neck loop antenna. This neck loop is actually pretty reliable and should not cut out of you turn your head.
By itself the ComPilot will not allow you to hear another person in face to face conversation, you will need a Bluetooth microphone, Phonak supplies one called “RemoteMic”.
It is not designed to be worn underneath your shirt, mainly because it has microphones that pick up your voice during a Bluetooth phone call.
A button press may be required depending on what you are doing. Most signals that are handled by the ComPilot can be started or stopped with one main button. It also has volume control.
I would encourage you to ask your Audi more questions before purchasing. If your don’t understand have them explain it to you again until you do understand.