Do you have a link to it? I can't seem to find it. Is it a chemical added to the pool? If so then like Flexible Solutions HeatSavr and EcoSavr (solar fish) or Natural Chemistry Cover Free, and similar products, they work OK when there is no wind but don't work as well in windy conditions. They aren't as good as a bubble-type cover, but they are better than nothing, especially if there is little wind.
As for retaining heat, they only prevent the heat lost from evaporation and not from conduction or radiation. Nevertheless, it's better than nothing and roughly half the heat loss is from evaporation (obviously varies based on the amount of evaporation and that depends on water temperature and air humidity).