smart:chain combines its processing modules into one integrated system. The modules share a single analysis of the source and work together within a fixed signal flow. This also makes smart:chain significantly more CPU-efficient than running the equivalent individual plug-ins at the same time. The plug-in additionally provides session-wide features such as multi-instance control, Groups, Front/Middle/Back depth staging and Auto Leveling.
The individual plug-ins offer more detailed control over their respective processing tasks. They are a good choice when you want access to every specialized parameter, need a different signal-flow order or only require a particular processor.