Interesting! To me inverting the x-axis just makes sense in 3rd person games: you see the back of the head of the character so if the back of the head moves to the left your field of view should move to the right. Basically, the joystick controls the head of the character from your POV. Never thought that was uncommon!

GameCube controllers controlled the camera by using buttons and not two thumbsticks

Played a bit of GameCube a few months ago and that's definitely wrong

the c-stick isn't great but it's very much used for camera controls

however the rest of the article seems pretty good. Thanks for sharing!