The linked article is a little over-hyped, but the paper authors themselves acknowledge that their system is simply a really cool example of parallel computing

The linked article is a little over-hyped, but the paper authors themselves acknowledge that their system is simply a really cool example of parallel computing and doesn't solve or avoid the P?=NP problem. From the paper: "...it is inherent to combinatorial and NP-complete problems (assuming P! = NP) that the exploration of the entire solution space requires the use of exponentially increasing amounts of some resource, such as time, space, or material. In the present case this fundamental requirement manifests itself in the number of agents needed, which grows exponentially with 2N. Effectively we are trading the need of time for the need of molecular mass." They could have implemented many different paralellizable algorithms, so the choice to solve a case of subset sum was probably for PR/the awesome factor (not to be underestimated as an academic motivation).