Correct me if I'm wrong, but from the
Wired article it sounds like they're using the cold gas propulsion on the test bed as a cheap fuel source that allows for a turnaround time of less than an hour specifically so they can cheaply run a lot of tests on the navigation and control system without worrying about pesky things like fire, crashes, and exploding million dollar test engines. It's certainly a great idea and should help prevent some future
embarrassments, but I can't really see how you can get the specific impulse high enough to make it feasible for a main engine for an actual mission. Especially since it sounds like the missions the CMSB is meant for are going to be one-way trips where turnaround time is unimportant, since it won't be. So kudos for saving money and time in development, but I'm still wondering if cold gas is going to be the propellant for the craft in service.