Yes, using a hot water recirculating pump prevents the water inside the pumps from freezing. Pumps for recirculating hot water maintain the flow of hot water through your plumbing system and bring it back to the water heater.
As the water on the hot water side of the pump cools down, a sensor valve on the pump turns on, forcing the water to be pushed back toward the water heater. The valve will auto shut off when the temperature in the hot water line reaches 98 degrees Fahrenheit.