That's a really good point. Interestingly, the Nature Letter (paywall) [0] doesn't seem to mention the aerospace industry at all. It's more targeted toward structural and automotive applications. I'm not sure where The Economist picked up the aerospace narrative.
From the conclusions of the Nature letter: "These findings provide a new alloy-design route to lightweight steels, demonstrating that the combination of specific strength and ductility accessible to steels is greater than previously thought, and increasing the density-compensated tensile damage tolerance of structural metal for terrestrial applications."
Yeah, I don't know much about the auto industry. The basics of stiffness driven designs, though, I suspect would be the same. As would the desire for lower weight. The obvious difference being that when we made a single satellite, material costs were negligible. When you make millions of cars, they're not. That said, there are probably quite a few steel parts in a car that are not stiffness driven, so that could be a big deal if this material works out.
As I understand it, at the macro level auto design is mostly stiffness-driven. But since they use stampings everywhere, strength matters since stronger materials can be made thinner without buckling (hence your roughly tubular section is stiffer for the same weight).
From the conclusions of the Nature letter: "These findings provide a new alloy-design route to lightweight steels, demonstrating that the combination of specific strength and ductility accessible to steels is greater than previously thought, and increasing the density-compensated tensile damage tolerance of structural metal for terrestrial applications."
[0]: http://www.nature.com/nature/journal/v518/n7537/full/nature1...