Hybrid method for making stuff louder
What i like about this (based upon in-depth comparison tests between many maximizer, clipper, and limiter plugins), is that it seems to compromise halfway between the extremes of "pumping" and "distortion" which volume-pushing compression methods generally seem to choose between.
Some plugins will stay perfectly clean at all times yet "pump" the audio, while others will maintain transient response at the expense of sudden distortion when pushed too hard.
Waves OneKnob Louder is one of the very few "maximizer" plugins i've encountered which has a healthy balance between the two extremes. Due to this approach, it is extremely versatile for use. You could theoretically get away with using it to beneficial effect in tiny amounts on just about every stem, group, and master buss.