Also note this is a side-effect of the fact that mammals lost true 3-color vision then primates re-evolved it by mutating the yellow cone into green/red cones. If you look at the sensitivity of red/green cones they almost overlap, as opposed to blue cones which have a more reasonable placement on the spectrum line. If you look at say birds with 3-color vision their distribution of cones is more like our blue/green spacing in the spectrum.

I believe the leading theory is that red light is given off by a variety of fruits when ripe so arboreal ancestors with that mutation could much more easily locate food. To most mammals red ripe apples and green unripe ones are all just shades of yellow so the mutation would have been like a superpower: the equivalent of eagle-eyed vision.