For static views, this would not be too effective, for the areal representation Nathan alluded to, but also because color gradients are not too effective at presenting precise values, and the third dimension of height will also be difficult to judge. So if you count color and thickness as halfway effective dimensions, then maybe it’s 4-dimensional after all.

That said, I imagine if you use this tool to show trends from time A to time B, it could be very effective, on the order of the Gapminder animated bubble charts.