Why A320/330 use C* FBW control without speed stability?
Many accidents have shown over and over that once the handling becomes muscle memory, the cue that having to pull harder means you are losing speed is easily missed anyway, so it's not as important as it seems.

So the artificial neutral stability instead decouples the controls: stick for flight path angle, thrust levers or A/T for speed. Nice and easy and you don't have to fiddle with the trim button that most pilots end up pressing rather mindlessly.

Large aircraft tend to be flown with auto-thrust all the time anyway, including e.g. a 777 which is stable in pitch and has trim. And when they are, the logic is rather like Airbus—control column for flight path angle, maintain flight path angle when released, just after changing speed you have to fiddle with the trim to get it stable again, which Airbus Normal Law does for you.

Note that aerodynamically all Airbus aircraft are still longitudinally stable, so if the sensors fail and the system degrades to Direct Law, the trim behaves like in any other aircraft.