Yes we did back when we caravanned all through the year, saved having to drain down completely to avoid frost damage.
Most times I used a thermostat switched electric fan heater as the Alde's minimum of 5 degrees is a bit higher than needed, but have used that on those occasions when it was the more expedient method.
When van properly drained there is little point, other than I tend to like to periodically use systems like this, rather than leave unused for months.
The higher cost of energy today might make a difference, if we were continuing with our all season caravanning. But in reality a stat set to just above freezing would see little running time here in the southern area.