[70Sixter]

Adjustables allow you to vary the pre-load the bars for different track conditions. I suppose for street also, but you'd figure out your setting and probably not change them very often.

In road tests some cars show skid-pad results that differ in g-force depending on which direction the test was run. You could conceivably compensate for that.

On a track you could set up based on the number of fast vs slow corners. Or if your car has been corner balanced you could fine tune to match.

I had them on my 70 911 and never had enough data to know how much difference they made.

In general I'd say they only benefit highly skilled and perceptive drivers on the road.
On the track you need a sensitive butt or a good pit crew.