Hi,

If you have Bosch ESItronic there is an excellent bulletin which gives a very good technical/chemical explanation of why you should not use it in many applications.
Basically if you have aluminium alloys and steels in close contact and you add a layer of copper this will react with saltwater to produce galvanic corrosion.
Why people persist in using the stuff I don't know. There are plenty of better alternatives. BMW have sold sachets of the correct lube for years. The other problem is that when it is used on things like clutch splines it dries out leaving a copper powder residue.
Most manufacturers have issued bulletins warning against it's use. Porsche issued one a few years back because mechanics were using it where the alloy wheels mate to steel hubs. For many applications, high melting point lithium based greases work best.

TW