But in VR we can have even lower latencies for synthetic content.
Because we have the head tracker recent history, we use prediction on pose trajectory, and can effectively know where the head pose will be at the time the current rendered frame will be displayed. And use that predicted pose to render the scene. That type of optimization won't be possible with see-through VR or AR.
The second optimization is timewarp, where the rendered scene is distorted in screen space after the fact, based on post-render tracker data (just a few ms before display). I wonder if that type of optimization would create artifacts in AR.
zipppy says "what if AR was delayed 15ms to make it equiv. to VR".
Zipppy's intent was to make AR compete with VR, not HVS.