WTH: Why white temp / rgb dissapear when off

If light source supports white temperature or is RGB, its card shows up warmth or RGB (or both) settings until the light is turned off.
Then white temp / rgb palete dissapears. The only slider which remains is brightness.

It works like this with lights from HUE integration but also with mqtt template light (Shelly RGBW2)


Most lights you can turn on with the brightness control. Hence it is visible when the light is off.

The colour and or colour temperature of a lot of lights cant be adjusted when the light is off. Hence not shown.

Spanners to that idea though are my Lifx lights. You can set all the attributes when the light is off but it appears like this:


So, good question.

Mentioned Shelly RGBW2 also allows to set every channel as well as brightness while turned off.