That bit is fairly easy to understand. Warm white (low colour temperature) LEDs aren't as efficient (they don't produce as bright a light for the same power inp

That bit is fairly easy to understand. Warm white (low colour temperature) LEDs aren't as efficient (they don't produce as bright a light for the same power input) as cold white (high colour temperature) lights. So if they just go down the options looking for the most efficient LED, that's what they will choose.