It must be noted that the Eagle Vision re-created by the System was a combination of intuitive senses and eyes. On the screen, the players could see that important objects were highlighted while the background turned gray.
The players could use this skill to do many other things besides finding certain objects, including seeing through things, sharing visions, marking targets, and tracking, etc.
Eagle Vision could also locate targets, which had helped Altair in his final battle with his mentor Al Mualim, who created many illusions of himself with a Piece of Eden. With Eagle Vision, Altair had detected Al Mualim's true self hidden in the crowd.
It was why his mentor Al Mualim lost to him even though the former had the powerful godly artifact.
When Eagle Vison evolved to Eagle Sense, it could heighten all the user's senses, allowing them to foresee danger and see certain scenes in the past or in the future.