If all you do is log in once a week and complete Coil, then maybe you don't appreciate it. In Coil, AoE circles were always easy to see due to the level designs and outlandish color schemes. But try Brayflox's Longstop, or outdoors in certain weather/lighting conditions, or in busy FATE scenes like Odin or Behemoth or the King Behemoth battle in Labyrinth of the Ancients. There were so many situations that made the AoE circles being a simple red clump get swamped and nearly invisible due to lighting, color filters, and other effects. The AoE circles are so clearly visible now, no matter the circumstances, the pulsing only helps to make them visible and have you staring at the ground less. Opening you up to focus on other things.

I think these new AoE circles are so much better now, and I'm not colorblind.