Kind of like when you're playing on-stage with a classic pedal-board. You do not rely on watching the pedal LED to know if it is engaged or not (if the stage light is red you won't even see it) but you normally know which effects you have turned on or off at each time.
I have been gigging with the FCB1010 for many years, controlling the Ax-FX Standard, the Axe-FX Ultra, and and the Axe-FX II. Before the Axe-FX it was controlling a refrigerator with multiple rack units.