Earlier quoted context omitted.
I guess some of us are old enough that wrong numbers were a thing and it was just polite to let them know. Especially when it sounds legit
Wrong numbers generally used to be caused by misdialing. Nobody dials numbers any more.
It's good to have a few numbers memorized. What happens if your phone dies, and you need to call someone? If you don't know any phone numbers, you have an problem.
I dial a few of my contacts by number, just to set them in memory.