It's a certification requirement. The airplane flies fine without it. I've found that often it's best turned off because as a pilot I can do a much better job and create a better ride for the passengers than the yaw damp can do. Any time I'm in turbulence or rough conditions, the yaw damp comes off in favor of footwork, in that airplane.
As mentioned above, with the Raisebeck strakes, it's a non-issue.