I have seen rod tips broken when hit by large deceivers. The mass of the hook is enough if it strikes the rod; a 4/0 hook in an 8" long deciever traveling at high velocity will take out a tip just as well as a weighted fly. Casting weighted flies should be no more tiring than unweighted if matched with a proper line and rod for the weight and size of the fly.
The jigging action of weighted flies often provides and important trigger that draws strikes when non-weighted patterns do not. Unweighted flies like deceivers and sea duecers are often just the ticket in shallows or over weed beds. It pays to have a good selection of weighted and unweighted alternatives.