Never understood why Nasals used the secondary effect of controls to fly approaches.
When engaged, the AT moves the throttles as required to try to achieve the speed.
Only when the flight guidance system mode is in "Open Descent" (Airbii)/"Flight Level CHange"/Real Boeing/"Level Change"(others) does the AT generally go to Idle/Standby: in these modes the pitch position is used to control the speed (ala Nasals). The trap in this mode is, if hand-flying and ignoring the Flight Director (which probably is saying fly down) by pulling up the nose, the speed will reduce but the AT won't react. If the speed gets too slow because Bloggs continues to pull/hold the nose up, any decent AT system will spring to life regardless of previous pilot selections and save the day.
Apparently the 777 doesn't do this.