The mental imagery of denting, bending and crushing a transparent glass-like material and having it react the same way aluminium would is immensely satisfying for some reason
And for when you wanted to dive a bit deeper and make your shop really pop, there was the Funky Chickens HTML Help Page (http://www.funkychickens.com/main.asp)
barring overtly offensive/shocking material, do we really browse the internet with enough removal from the content we are viewing to consciously recognize (and take long-term action) when a website is making us uncomfortable? the position being put forward by this extension is 'no', though your point is valid in a general sense
If I read an ebook and it really hits home for whatever reason I'll buy a paper copy. Not to read, but to act as a sort of physical reference point to stop me from forgetting about its existence. A souvenir of itself.