"It's for everything" can be misunderstood, so let's be clear; it applies to both trap-detection and detection of secrets. Basically, it applies to all instances where you would see or notice something based on your Perception.
Traps, switches, buried chests, hidden buttons, you name it, Light Stepper should help you find it, unless things have changed (and if they have, oh boy is Light Stepper more useless than ever).
