I'll have to go with RKS on this, as I have not seen any difference on these lowly 50cc and 150cc scooters by changing from copper core to iridium. However a simple change from a single ground electrode to multiples would increase the compression ratio in these scooters. Of course this results in slight increase in power.
Bosch has engineered and produced 3 and 4 ground electrodes for years, and especially the 4 ground electrodes do last longer especially in poor quality fuels that literally eat the electrodes.
I would believe more that it is more marketing than anything else, because there are too many factors that come into play such as fuel quality, air volume and density, O2 levels, humidity, wear, load,etc-- not to mention location of the diamond opening relevant to the intake port. Most of the field condition claims would not be repeatable and thus would not be scientifically provable.
here is their picture of the plug, grab a copy, enlarge it and think about it yourself.
http://e3sparkplugs.com//media/banne...plugs_cars.jpg