They make them so you can go below ambient with your cooling solution. For instance if your ambient temp is 70F then the best you could ever possibly do with fan/heatsink is greater than 70F, which while not bad, doesn't allow pushing the hardware further beyond its limits. With a peltier or piezo electric cooler (same thing) you create an artificial temperature differential between the plates. If that differential was say 40F then if the Hot plate was kept at 70F then the Cold plate would be at 30F.
The problem with this, is that the CPU will try to keep the Cold plate at 190F (or higher) and the hot plate at 230 (or higher), so instead of your HSF(heatsink/Fan) needing to cool 190F to 70F it must now cool 230F to 70F, requiring a larger HSF, or a better form of cooling.
In theory, you could stack TECs to gain even further performance, bringing the temp of the chip well below 0F, But you still have to find some way to cool the topmost hot pad to near-ambient, or the whole thing goes poof.
A further Problem with TECs is that they can only transmit a certain amount of heat before they die. The amount of heat they can transmit is generally based on the quantity and size of the individual piezo elements. the more the better. You can improve this ability to transmit heat by putting more piezos together in parallel, but this requires more electricity to accomplish.
In short, the IOpener is far less than the ideal placement for a TEC.
