My impression of steering dampers is they work in the upper ten percent of a bikes capabilities, to prevent increasing frequency and duration of front wheel oscillations
They only work when you've gone full throttle in a turn, a dog attacks your front crashbar from his front porch setting off a tank slapper....the bars snap back and forth so fast it tears the bars out of your hands
With...the tank slapper slows and stops it's oscillating with a chance to recover
Without...spit you off into the bushes in a different direction
There was a lot of that tank slapper crap (even without a dog attack) 60-70s when dinosaurs roamed the earth.
Yes they effect straight line, slow parking lot and the highway straight but my impression that is secondary. They don't do nothing until your about to be killed from a violent wrist breaking tank slapper