My keychain is significantly smaller in Korea. I have lived in two homes in Korea, and each had a keypad on the door. You simply set your personal code when you move in, and you never have to carry a key with you. It’s perfect for when you are going out for a run or to walk the dog and don’t want to carry anything with you. It’s also highly convenient for letting close friends come to your house. Just share your house code, and they can come over when needed. The keypads also makes me feel quite fancy and modern.