It opens up people to talk about what they want to talk about. It works for people you know well, haven’t met before, and anyone in between. Even with people you know, saying “How’s work” “How’s the kids” “How’s…” just forces them into that one subject. Possibly, something unpleasant may have happened and they particularly don’t want to talk about “…”

Also, personally, I’m terrible at remembering things about people after only meeting them once or twice. This keeps me from asking about a job, kids, hobbies, etc. they may not have

EDIT: This also opens up a chance to learn about something new and interesting. Or find a common interest you may not know you had with this person.