The growth of renewable energies elevates the significance of maintaining system balance and imposes more demands on regulation resources. Flexible loads have been extensively regarded as prospective regulation resources for providing ancillary services within power networks, including frequency regulation, primary reserve, and synchronized reserve. However, the dispatch of flexible loads presents the challenges of frequent data transmission and explosive data volume, leading to substantial pressure on communication networks. To improve the communication performance for providing effective ancillary services, this paper proposes a coordinated optimization framework for dispatching flexible loads in data valuation-aware power-communication coupled networks. The framework employs: 1) a data valuation approach considering inherent characteristics and ancillary services to distinguish the data transmission preference; 2) an analogous model of communication networks to power networks, formulating the relationships between different components (e.g., nodes, branches, et al.) within coupled networks; and 3) a coordinated optimization model for coupled networks, which analyzes the impact of data valuation-aware transmission in communication networks on the dispatching of flexible loads in power networks. Numerical results demonstrate that the proposed coordinated optimization can effectively allocate regulation resources by considering the limitations of communication networks and significantly improve the regulation revenue engaged in hybrid ancillary services.