Grounding with a Earth box?

I think the alternative to such boxes is having a solid rod planted deep in the ground outside of your house with a ground wire running to a single grounding point for all of your gear.  Why this is important, I don't know.  But, I do know it does affect how a system sounds.

I heard a demonstration of the Nordost grounding system.  It consisted of such a box to which all components are connected via a run of wire from an unused input to the grounding box.  Nordost supplied wires with all sorts of alternative connector plugs to fit that unused input (RCA, XLR, BNC, etc.).  With the grounding installed, the biggest change in sound was to the imaging of the system -instruments and vocalist seemed to float more freely in space and seemed to be actually present in the room.  The decay of notes also seemed to be more obvious and natural sounding instead of sounding cut off.  I liked what I heard. 

I did not get to hear it in my own system and did not ask for an in-home demonstration because my amplifier does not have an unused input.  I was told that a chassis grounding point was NOT an alternative to an unused input for this grounding scheme.

I cannot say whether or not any improvement from using one of these grounding boxes is "worth the money," but for some context, I thought the Nordost system made a bigger improvement in the system my local dealer used to demonstrate the product (high end system) than did power conditioners or high end power cords (as compared to decent but not extremely high priced cords).  The improvement in clarity and soundstaging  was quite impressive.