It seems like you think that contradicts what I said. The system by design adds a little trim in very specific circumstances. That's not the same as being neede

It seems like you think that contradicts what I said. The system by design adds a little trim in very specific circumstances. That's not the same as being needed because the aircraft is aerodynamically unstable. That is a term which has an actual definition. That said there are airliners out there which are unstable in the longitudinal axis and require a yaw damper to prevent Dutch roll.