pikkle's reminder in the "Wikipedia as WHS" post about the future of Virtual Reality (VR) raises an interesting possibility under this subject!!
It appears certain that, in the coming years, a VR experience is going to become available via the Web which would provide what, in many respects, would be a "better" viewing experience of many sites than can be obtained in person. I am thinking particularly of archaeological sites and buildings. Never closed, no hordes of people, access to all areas, ability to "fly" in close up, World class knowledgeable "guide" etc.
Where would that leave the actual "visiting" experience in comparison? I understand that there is a Taoist saying "the journey is the reward" (more frequently in English - "it is better to travel hopefully than to arrive"). Is it not a fact that for most/all of us the journey TO/FROM a WHS is an aspect of a visit which is absolutely necessary in order to provide a "complete" experience? However, we may need to accept that actually "seeing" a WHS in all its detail, may well be "better" achieved via VR!
An analogy which occurs to me as an opera lover is the comparison between watching a live opera given by what might well be a "provincial" middle ranking company or watching the Met or La Scala on an HD livecast with world class performers. I would USUALLY (but not always!!!) choose the live opera and would also choose the "live" WHS visit over the VR. As an inveterate "listophile" I actually keep a list of "seen" operas BUT do NOT include operas seen by transmission on that list!! I suspect that, even if top quality VR visits to WHS become possible, I wouldn't be "counting" them - though I would be very happy to view them!