This is a neat concept, though I was not terribly impressed with the quality of the depictions in the overlays. Also, I thought it didn't provide enough context or information about most of the sites that are covered. I think the author passed up on the opportunity to talk about how long looting/dismantling has been going on, though for some of the sites he does allude to dismantling in the medieval period.
Part of the problem is that many of the sites are really ruins. i.e., there's not enough of what used to be there to really let you envision it.
How much of the past in the form of buildings should really be preserved is something that I ponder a lot, so this was more food for thought in that way.