Traditional tools only allow for points to be connected by two lines. Exothermic allows you to create shapes that connect as many points to as many lines as you would like.
Simple shapes only allow each point to be connected to 2 lines. Shapes can be drawn so that they appear to be connected but making any changes is tedious.
Complex shapes can have points connected to an unlimited number of lines. Any changes made to interconnected shapes will affect all the connected shapes.
Complex shapes open the door to new tools that can be used
The extrude tool supports both points and spans.
The Spiral tool creates spirals off of any selected points, and because of complex shapes everything stays connected.
Just because complex shapes allow for everything to be connected doesn't mean they have to stay that way. Use the detach tool to break pieces off.