background-attachmentproperty has never seemed all that useful to me. I have always looked at it as some sort of old school design trick from the GeoCities days to get a repeating background to stay in place during scroll. Turns out a background with a fixed position can be much more useful than that.
Some nifty examples of the
background-attachment CSS property. I really like how you can use this to achieve a fairly dramatic effect with relatively little effort.