The Curve Tool can more easily affect the color balance, either by design or by accident. For example, if you want the reds lighter or darker, but only in the highlights, you can do that by adjusting the tones in the red channel. The main Color Tint tool will affect all tones of the color, where the Histogram and Curve tool can be selective as to tones. The effect of adjustments to these controls is cumulative. You can tweak the histogram Points, and then go tweak the Curve Master channel curve, and then the Green curve alone, and you will get the combined result of all such tweaks.
Considerable adjustment runs the risk of hitting the limit which saturates the color.
30 bit and 36 bit scanners offer more range before that happens. The Clone Tool is great to easily remove dust spots . Touching up a few spots can make a dramatic difference in the perceived quality of the image. Here's a detail or two about using the VERY important Clone Tool . PhotoImpact, Paint Shop Pro and Photoshop are all very similar too.