I have a Forest River Travel Trailer, so it may be (is likely) different.
I have two 90 degree turn valves in red & blue at the rear of my TT to drain the water lines, but the fresh water tank drain is a white slide valve, similar to the gray/black water dump valves, located directly underneath the fill hole for the fresh water tank.
Draining the water lines will not drain the fresh water tank. I guess it is possible that you could partially drain the fresh water tank by turning the fresh water pump on and opening those two 90 degree valves, but the dump valve is faster, probably fully empties the tank, and doesn't run the risk of the fresh water pump running dry.
2020 Chevy Silverado 1500
Forest River Wildwood XLite 263BHXL