Do you look for a switch or a knob in a dark?
We work in a dark many times.
The Panel Assistance function glows all LEDs on the panel just a little to give you a hint of their locations. It was introduced with PM5D many years ago. And it is now available on TF series too.
Go to Preference 2 and turn "Panel Assistance" on to use this function. Only when brightness value is 5 or less, panel LEDs are dimly lit.
Go to User Setup and open Brightness page. When Panel brightness is set to 9 or less, Panel Assistance is automatically turned on like the one in the picture.
Because of its LCD touch panel, OLED channel name screen, and keys with glowing function name, TF is easier to operate in a dark room.