They’re ridiculous and if one fell over it could be the bridge all by itself. It comes down to the fact that almost all the cost and effort is in the machinery, so is it worth it to hold a project up over 10’ of tower? Probably not. It’s like asking if you’re going through all the effort to buy a truck to drive to work 10 times a year, does 15 miles matter more than 10? Not really because all the cost is in buying the truck.