Why do jeans have this little pocket - Simple Things

[Ilsa]

6. A single key? It would be worn securely

higher on the hip with the shallowness of the pocket and be less likely to poke the much lower abdomen if using a front pocket or the butt if using a back pocket. It's probably functionally obsolete as car keys are disappearing in use, or because keys are usually carried in multiples, sometimes with mini discount/membership cards or elaborate key rings. But style lives on!