You will agree that RGB must have power to lit up. Plus power to RGB controller if PC have such thing. Power demand for a nice chain of bright LEDs may rise to few or even above ten watts in extreme cases. So add some 10% to power requirements in case of extreme RGB addiction syndrome. In PSU choice it mean requirement for +50W model in addition to the power demand of the rest of system. Where all extra power is wasted into disco lights. Brighter LEDs are hotter as well. Sometimes even cause freezes and bootloops (
the tale of HyperX Fury RGB SSD). Well, I'm not against RGB as thing. However currently they are turned into stupid trend where gaming hardware = RGB. It gone so far that now it is much harder to purchase DDR4 3600+ MHz RAM modules without RGB nonsense than ones with RGB for 30% extra price and then figure out how to turn your little rave party inside PC case off by default.