This basically means that the US military has found these models A-OK and approved their usage by the US Army officials, adding them to the Approved Products List for the US Department of Defense. Receiving this approval was a difficult task for Samsung, as it is, as silly as it may sound, a matter of national security: military officials should only use the safest and most efficient communication devices for their official business; therefore, Samsung smartphones had to fulfill one hundred unique requirements before being accepted. These requirements ranged from intrusion detection to support to encryption.

I guess what this means is that whenever we see a general or other big US fish in khaki, there is a high chance he or she will be using their Samsung smartphone.