Copper plate is often used as a prep step for plating other metals, such as nickel and silver. It also (usually) increases the conductivity of the metal to be plated. [A_Steingrube] is using the ...

Because this gives you a solid copper plane to facilitate plating of the vias. The order of operations is, drill, plate the holes, photoresist, gold plate, etch.

A demonstration of electroplating a copper coin with zinc. Purifying copper. Another use of electroplating is to purify copper on an industrial scale for use in electrical wiring: ...