This is the quantum efficiency of a modern mono sensor:
And it’s color version:
And here are the spectra of some daylight situations:
So you see the blue light wavelenght is a little bit lower (in dB), I think that is the reason of the combination. But I might be wrong!! Was also wondering what would be the best bnrightness for the blue leds’s since as you see the quantum efficiency is lower for the blue colors, and you might compensate for it.