Area Charts are usually used when you need to show changes in amount of something depends on time or another changing value (which can be demonstrated on the X-Axis). 3D Chart is a modification of 2D Chart. It does not have an additional Z-Axis, forming a third dimension, it only looks volumetric. So, the difference is in the chart’s appearance.
This Chart has two 3D Area series demonstrating how the ACME Corp. and a competitor’s company shares prices were changing from 1996 till 2005. The minimum value for ACME was $113 in 2001 and for the competitor’s company it was 23 in the same year. The maximum values were $215 in 1996 and $195 in 1995 accordingly. There are two years when the competitor’s company share price was unavailable for some reasons (1994 and 2002), so you can see the gaps in the second Area series. The Y-Axis holds the values of the prices in dollars, from 0 to 240, and the time period is displayed on the X-Axis yearly.