A common definition of pivot chart is a graphical representation of the data in your pivot table. Although this definition is technically correct, it somehow misses the mark on what a pivot chart truly does.
When you create a standard chart from data that is not in a pivot table, you feed the chart a range made up of individual cells holding individual pieces of data. Each cell is an individual object with its own piece of data, so your chart treats each cell as an individual data point, charting each one separately.
However, the data in your pivot table is part of a larger object. The pieces of data you see inside your pivot table are not individual pieces of data that occupy individual cells. Rather, they are items inside a larger pivot table object that is occupying space on your worksheet.
When you create a chart from your pivot table, you are not feeding it individual pieces of data inside individual cells; instead, you are feeding it the entire pivot table layout. Indeed, a true definition of pivot chart is a chart that uses a PivotLayout object to view and control the data in your pivot table.
Using the PivotLayout object allows you to interactively add, remove, filter, and refresh data fields inside the pivot chart, just like in your pivot table. The final result of all this action is a graphical representation of the data you see in your pivot table.