Jumping spiders may use color as depth information
In a Veritasium video about jumping spiders at 27:21, they bring up the speculative possibility that color could be used specifically to perceive depth. 1
Jumping spiders have multiple layers of photosensitive cells at different distances from the lens. Many jumping spiders can only see two colors, but they still have four layers of cone cells, with the farthest two for green. The speculation is that things in green will appear in different levels of focus, creating depth perception in that color which spiders can use. However, this also leads to a weakness as well: Prey can use colors or patterns of colors in a way to create death illusions to throw off their predators and male spiders might display colors that they cannot see in order to throw off the female spider (which would otherwise try to eat them during courtship). 1