Canon has been selling protective underwater cases for their cameras for years, so why did they find it necessary to offer a tougher than average camera that’s waterproof even without a housing? First, because it was an unexplored market niche for them, and second because it simply makes sense. As the price of digital cameras keeps coming down, more and more people view them as expendable items that they take anywhere. Which means cameras are increasingly becoming exposed to rain, cold, drops and other abuse. So designing one that can handle those conditions is becoming important.
As far as waterproof goes, anyone into boating, kayaking, surfing, fishing, snorkeling or just hanging out by the water knows that taking pictures in the water and underwater is a wonderful experience. And being able to take photographs by the pool or at a beach without having to worry about the camera getting wet is priceless. Protective cases are a good thing, but they are big and bulky and certainly not what you want for a few quick snapshots in the surf. Further, even if you do use a protective case, it’s great to know that a potential leak (and they do and will happen) would not kill the camera.
As far as freezeproof and shockproof go, that also comes in handy. Being able to take your camera skiing, snowboarding or hiking in the cold is a good thing. And drops do happen. Digital cameras are small and slippery, and it’s all too easy to drop one.