Because of the *multiple* angled surfaces of the track, different head tube angles and fork offsets have dramatically different effects on handling. And that’s on a single velodrome. If the rider travels to other velodromes of different dimensions, there will be different experiences.

...then factor in rider speed.

I would imagine that this is similar to adjusting caster and camber on a race car. When it’s right, it’s awesome. When it’s not, then confidence plummets.