Using the 0-255 values it is possible to access the minimum light brightness (0% brightness in the UI, != 0 value, which means off) for lights in the UI (which corresponds to 1 brightness value). However, using the UI slider the minimum achievable value is 1% (which is equal to 3 absolute brightness), which is not the absolute minimum.
I attach a few screenshots.
Minimum brightness when set via bound remote of numeric “1” of 0-255 value:
Minimum value able to set using the UI slider:
And shown value:
In some of my devices there is a huge difference in brightness between 0% and 1%.