The Eye of Munin was the heritage of the Elves.
Passed down from the Elven Ancestor, Aragon, who first got it after gaining enlightenment from the World Tree, it had been their only way to rival the power of Sages at that time.
Sure, Emotions had its perks, but the allure of actually dominating the laws of the world was far more interesting in their opinion.
So they abandoned the Radiant Moon and focused on the World Tree.
It wasn't intentional but it happened and nothing could change that.
One could understand their reasons for leaving though.
The basic ability of the Eye of Munin was to see the truth of the world.
The essence of everything would become bare before the Eyes of Munin.
Illusions would no longer work, there would be nothing like obstacles, 360° vision as well as farsightedness.
It even predicted paths an opponent could and would likely take.
It saw through other techniques, deconstructing them for the user so they could counterattack in the best possible way.