For continuous flow units you promote the use of remote controllers, why?
Digital controllers allow you to select the exact temperature of the hot water at the outlet. This has a number of benefits:
Safety, especially if you have young children, the hot water can be pre-set to a child-safe level
No need to mix hot and cold water, this reduces the changes in water temperature when another tap in the building is turned on
You use your continuous flow unit more efficiently as less gas is required to heat water to 40 °C (typical shower temperature) than at 55 °C (which is the default temperature without controllers)
Highlights any problems (disruption in gas supply etc.) by displaying error codes on the controller