We have the automatic light activated by motion in our pantry. It's very handy. When you walk in, it turns on. When you walk out, it turns off...all on its own. After having us running up his light bill for four months because we can never remember to turn off a light, my father-in-law is wishing he had these installed all over his house before we moved in).
When we moved in I assumed it was for convenience's sake. You've got your hands full of food as you exit the pantry, no need to turn off the light, it just shuts off on its own a few seconds after you exit. Perfect for a forgetful momma like me.
It has come to our attention that the light has an additional benefit: uncovering thieves in our midst.
She wasn't actually trying to steal the chips. Joe challenged her to put them away without triggering the light. She got all the way in and stood up before it detected her.
Pretty sneaky, I'd say.