The title is not misleading, and the golden layer formed is metallic water and not any of the metals used -- where electrons are delocalised/shared between water molecules. They have strong evidence that the layer is indeed metallic water and not something else:

> Experiments at a synchrotron in Berlin confirmed that the gold reflections produced the signatures expected of metallic water.

In my opinion, the ingenious part of the experiment is the following part, and I'm glad that they were lucky enough to find the right conditions:

> The key to avoiding an explosion, Jungwirth says, was to find a window of time in which the diffusion of electrons was faster than the reaction between the water and the metals.

Edit: added "in my opinion".