The transition from unidirectional smart charging (V1G) to bidirectional charging (V2G) promises additional operational flexibility and reduced electricity costs for facilities. However, the economic value of this transition is not universal and depends strongly on facility-specific characteristics, including load profiles, electricity tariff structures, charging infrastructure, EV participation, and battery utilization. Whether the additional investment for V2G pays off, therefore, remains a key question for facility operators. This paper proposes a simulation-based techno-economic framework that addresses this question by combining smart charging simulation with a cost-benefit assessment covering electricity tariffs, power prices, infrastructure investment, battery-wear costs, and operational costs to estimate annual savings, payback period, and return on investment (ROI). The framework is demonstrated on a real municipal hospital in Dresden using measured load profiles and realistic EV charging scenarios. Results show that discharge capability is a key determinant of economic performance. The peak reductions achieved by both investigated AC configurations remain below the discounted annualized-cost break-even requirement, although the higher-power configuration achieves a simple payback within the assumed project lifetime and a positive undiscounted ROI. The economic conclusion therefore depends on the financial metric applied.