What are some interesting things about rural elderly people using smart phones?

This is about when my grandfather first started to use smart phones. Now I think about it, I can't even laugh. I called him that day, but no one answered. Later, I went home to have a look. As a result, my grandfather was so anxious that he didn't talk when he called. Only then did I understand that my grandfather couldn't answer the phone with this kind of phone, and he started to say, haha, now I think about it, it is very funny.