What Use Is An F-call?

What use is an F-call? I recently talked about making contact with a station on HF. Getting a feel for the other station is very important because it will make you understand when the other person is listening and when they're not. It will let you know to what kind of station they're responding to, and when they do respond, how they respond. I recently made a contact with T33A. I used 5 Watts on a rotatable dipole, 15m. I listened to the station for a good 10 minutes before I made my first call. They gave me lots of information about the contact long before I opened my mouth. It was one of the last days they were operating and it was bedlam on the frequency, lots of stations wanting to make this contact. The station told me that they were listening 10 up, so I configured my radio to deal with that. Then I worked out what the rhythm of the operator was, got a feel for how they replied and when I was ready, I called my callsign. I was floored that they came back with "the VK6 QRP station" on my fir