Linked from
The 9 pages that link to Depth perception, each with the reason it gives.
Visual perceptionRelated: It makes a flat retinal image appear spatially extended.
Optical illusionRelated: Depth cues can make flat images appear spatially arranged.
Hand-eye coordinationRelated: Judging distance helps set the reach and grasp needed for an object.
EyeRelated: Paired eyes provide binocular cues that support stereoscopic depth.