Weaponizing PlayStation:

The U.S. Air Force is buying 300 PlayStation 3 game consoles. Not to play games, but because it's the cheapest way to get the powerful processors that create the photorealistic graphics for PlayStation games. Air force researchers want to use these processors (similar to the ones found in high end video cards) to build faster computers for military use.

The CPU manufacturer was not willing to sell the PlayStation processor separately, at least for a reasonable price. So it was easier to just buy PlayStation 3s.