This is such a weird thing isn't it.

It's like this in the UK too, every conversation starts with "How are you?" "Fine, how are you?" "Fine."

It's always the same, pretty much. It's daft, it's just like a ritual that everyone is happy to partake in.

No one is actually asking you how you are, it's just a noise that both parties have agreed to start each conversation with. No actual information gets exchanged. You could easily replace those phrases with nonsense and as long as both parties are aware of the nonsense and what the nonsensical response is expected the it would work just as well.

Person 1: "Hippopatumus soup triage?" Person 2: "Triangle, Hippopatumus soup triage?" Person 1: "Triangle."

It's so strange.