While an area chart is similar to a line chart, it conveys the information related to quantum through shading. While a Line/Spline chart would be a good choice to show revenue trend or unit shipment trend over time, an area chart would be a better choice if you want to display cumulative revenue over time or cumulative shipment quantity over time.
A Spline area has the same advantages as the area chart and in addition helps in smoothing out asynchronous data points.
Fig. Area Charts
<<Spline Charts | Stacked Area Charts>>