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 compensation, and operational costs to estimate annual savings, payback period, and return on investment. 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. Under both investigated AC configurations, the achievable peak reduction remains below the economic break-even requirement, indicating that the V1G-to-V2G transition is not economically viable under the considered site conditions.