Dean if I understand you correctly I agree that bars can avoid an insurance claim with an excess to pay and a couple of years of higher premiums, but bars dont protect everything - they are not total insurance and this all depends on how much your excess and premiums are.
Drop the bike when it is stationary then yes, but with any off at speed the chances are that something that is not protected by the bars will get damaged. You would be very lucky in an off to have only the engine bars take the initial impact and then to slide down the road with only the engine bars and tyres making contact but I dont doubt that it can happen.
I would have thought that the handlebars on an F650 or F800 would most likely take the first impact but luggage/paniers and so many other factors come into play as to what gets damaged.
I would say that you should perhaps view engine bars as being more of an insurance that you wont have to abandon your trip/journey because you avoid putting a hole in an engine casing or in the case of tall bars you save your radiator or even protecting you from a crush injury. I would agree with you that for this reason they still have a value for road riding and not just off road as I said in my previous post.