My GH60 Rev C doesn't have full backlighting but does have a few lights - WASD group, the FN (split right shift) key, and some others. I use the lights as layer indicators. WASD light for FN, I have another toggled layer with lights under right shift, right control, - you know the arrow key setup like a Pok3r. Anyway, I'm using various lights as layer indicators with QMK. I've never used QMK with full backlighting, though.