Why define base point for changing size?

The Position and Size dialog for charts offers the option to change the base point for changing chart size. I understand the usefulness of a base point for specifying position, but I don’t understand the role a base point plays in determining size.

It seems to me that sizing a chart is not affected by whatever base point is selected. What am I missing?

It is affected. The base point for resizing tells which point of the object will not move when other points will change their position when stretched away from or shrinked towards the point.

Try fixing top right point and decrease size by half; undo, and repeat, this time fixing bottom-left corner.

Excellent explanation, as always. Just what I needed. Thank you, Mike.