Complex financial derivatives may not be as tangible as other engineering endeavors, however they do have tremendous value to businesses looking to hedge their risk and offer flexibility to their business models. The economic collapse caused by these complex financial instruments was not due to the Phd's that created these derivatives, but by the traders that didn't full understand the limitation of the risk models, as well as the moral hazard in packaging toxic assets into CDO's knowing they would easily be able to pass it along. Having said that, I'm glad I didn't sell my soul and become a banker ;)