>>3273738see the lit up section of the histogram when I hover over the slider?
Curves allow you much more precision, since you can plot multiple points for highlights/shadows etc whereas the sliders just apply evenly to that whole quarter of the histogram. They allow other things, like moving the black point and whatnot, but if you play around with them you'll see they can be used to apply a much more deft touch to how your shadows sink to black and that sort of thing.
