The whole “disposable device” approach to all technology needs to be reevaluated. I’ve heard it quite a bit but I’m not personally sold on it. It’s not environmentally or financially sound. Furthermore the Watch is far more personal of a device than the iPhone; it is something meant to be worn on our body for long periods of time, even during sleeping as it’s capabilities expand. If I had a tattoo I had to look at constantly I would want it to look as good as possible; and same for the Watch.
As far as the mountain bikers go; that may be a good situation for using the Ion-X Glass but are there more mountain bikers that bike to the extent of shattering their watches or are there more users who want to have something that looks nice that they are going to wearing and looking at most of the time? Maybe in the future we will be able to order specific case material and crystal materials to our preferences; that would be a great option!