I took a peek at the discussion for Advanced PTZ motion here.
I don't quite understand the difference between the virtual and absolute positions but the cameras at our studio do support simultaneous movement when moving to preset virtual input positions.
My understanding is that, currently, virtual inputs can only be created if the camera is at the desired position. The only other motions available are eight major cardinal directions.
What if we wanted a camera to follow an arc with generated virtual inputs?
The only two ways I can imagine implementing this would be either saving a PTZ input at each landmark point along a movement path (tedious) or make an approximated shape by zigzagging with the cardinal movements (aesthetically displeasing).

If we had virtual input parameters, we could generate camera movement paths of any shape and any complexity.