In contrast to space-based weapons like Brilliant Pebbles which, thanks to their ability to attack ballistic missiles early in flight trajectory and, thereby, to destroy multiple warheads with a single interceptor, have the potential to be more cost-effective than offensive forces stand-alone, ground-based defenses can only attack incoming warheads after they have been dispersed from the launching missile and in their final stage of flight.
In addition, the Acer C7 Chromebook is incredibly affordable as a stand-alone product, and even more affordable when schools consider the reduced total cost of ownership thanks to its manageability and security features.