I actually thought the same thing about Platinum and was surprised to see them installed.

Copper's melting point is 1981 degrees F.
Iridium's melting point is 4449 degrees F.
Platinum's melting point is 3224 degrees F.

Copper's Tensile strength is 20,000 PSI.
Iridium's Tensile Strength is 160,000 PSI.
Platinum's Tensile Strength is 20,000 PSI.

I think the issue people were having lie with the Bosch Platinum's and I think that's why Audi went NGK..

________________________________________
The BMW M Roadster, if you have the means I highly suggest you pick one up. It's so choice....