The benefits of using PICVs in HVAC systems include reduced energy costs, increased occupant comfort, and improved system performance. By maintaining a constant flow of hot or chilled water to the coil, PICVs ensure that the system operates at optimal conditions, regardless of changes in system pressure. This leads to better temperature control, reduced actuator operation, and fewer callbacks. Additionally, PICVs eliminate the need for balancing and rebalancing during commissioning, making them a convenient and cost-effective solution for HVAC applications.