Me? I took a bus at 2am from Taupo to AKL and got in about 8am. Flight was 3:30pm or something. You can get a lot more done if not dragging a 20kg case around with you, not that I felt like doing much given I hadn't slept for 24 hours mind.

In more recent cases, it's been when I'm travelling with a friend and one of us needs to be at the airport crazy early (or leave separately).

Most recent case, I checked in, got my friend checked in at priority then he had to sit around waiting for two hours until he could bag drop. Once he got through I guested him into the lounge. This was his first and probably last ever lounge visit. He was not impressed and actually preferred to roam around the rest of the airport.

I don't know why AC have this policy. Is there some sort of cost associated? Are they worried about losing or delaying a bag? As I understand it, the process is pretty automated and reliant upon the airport technology and staff once it gets dumped onto the belt.