An RGB monitor light bar does a job a plain desk lamp cannot. The front emitter throws a wide, asymmetric pool of white light onto your keyboard and notebook, while the rear emitter washes the wall behind your monitor in colour. The result is a workspace that is easier on your eyes and far better looking on camera.
Working against a bright screen in a dark room forces your pupils to keep adjusting between two extremes. Filling that gap with a soft glow behind the panel reduces the contrast your eyes have to fight, which is the same principle behind bias lighting in video editing suites.
Want the full picture? Compare the range in the 4 ambient backlight modes guide, or start from the complete monitor light bar collection.