The spirit of that rule was to add clarity to the scenario where a guy is falling or diving to make a catch, and only has possession for a split second before hitting the ground and losing it.
I don't think it was originally intended for a guy that catches the ball, gets a knee (which equals two feet), pivots, reaches, and then slams the ball across a goal line.
It used to be "two feet and a football move" which makes all the sense in world. That would prevent it being called a catch when a guy doesn't control it after getting an initial two feet, but also allows common sense to be applied to when a guy has the ball, two feet down, and then makes another move which illustrated possession