The recently introduced concept of virtual storage plant (VSP) focuses on optimal coordination of a large number of distributed storage devices (of the same or different technology) to provide multiple network services, e.g., primary frequency response (PFR), voltage regulation. In this paper, the potential benefits that VSPs can bring about are discussed from different perspectives, including the potential to reduce network investment needs, improve reliability at the distribution and transmission network levels, and provide service to the grid. VSPs are expected to provide the grid with flexible operation to facilitate high penetration of renewable generation. In order to achieve this thought, mathematical tools are to be developed, which optimally coordinate the storage units comprised in a VSP. This aspect is particularly explored in this paper. An illustrative case study is discussed, which shows how VSPs comprising battery storage systems can effectively support frequency regulation when the storage units are optimally managed.