Sorry, didn't mean to disagree. It was offered more as an aside than anything, since the piece is obviously of other materials besides gold.
I would imagine that in the case of gold plating (at least with 24K) the concern would be abrasion to the gold and corrosion to areas that weren't completely gold covered. The corrosion might also creep under the gold. "wherever two different metals are brought together they react due to their potential gradient. " What do you mean by "react" here? As I understand it, in electroplating metal ions are reduced and bond to the substrate by the shared electron. Oxides (like rust) form when oxygen bonds to the metal, helped by water or some other solute.
We're probably saying the same thing, just in different ways!