Earlier quoted context omitted.
Of course - if nobody used it Amazon would remove the button. I doubt that adding 1-click to some other site will greatly increase their sales - that is all I'm saying.
Well, you would be wrong. Every step between a customer and completing an order is a loss of sales.
Then there has to be some sort of measurement out there on how each step causes cart abandonment (or whatever it's called).
Its the same reason sites add Single-Sign-On... click click, I'm on a website... vs filling out forms, verification, etc...