https://youtu.be/nfAqTSjMBJk?t=1641

Watching a Veritasium video about jumping spiders and color. At 27:21, they bring up the speculative possibility that color could be used specifically to perceive depth.

This would show up in jumping spiders specifically from the fact that they have multiple layers of photosensitive cells at different distances from the lens. Even though many jumping spiders can only see two colors, 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 that spiders use.

This also leads to a weakness as well: Prey could use colors or patterns of colors in a way to create death illusions to throw off their predators. 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).

Regardless of if this is true for jumping spiders or not, I feel like this is a paradigm shift in how colors can be understood.