IF the orbital test works then it will lead to interstellar travel and shrinking it down would give material that would have anti-gravity like effects. We would spend the money to make nanocavities so that we could have propellentless thrust for floating cities. All of space and propulsion related science fiction would become possible within about three decades short of faster than light. This drive is in orbit now for a few months. I think DARPA gave them more money to conclusively prove if it works or not. All of the ground tests show it might work. But if it proves out then we first get 1000 times better than a hall effect thruster but with no fuel limit. No fuel is used. So long as you have power, solar or nuclear the drive keeps working. So nuclear fuel supply for decades then thrust for decades. The theory proves out, then we make nanocavities which could act like antigravity then we get 1G or even 3G thrusters in space. This would be the Expanse TV show tech. 2 days to Mars using constant 2G acceleration.
The current version requires an energy source. The nanocavity version would not.
My first response is IF.
Less than a week, relatively inexpensive, trip to other planets and the asteroid belt opens up trade. It is a whole new frontier without having to suffer a technology starved frontier lifestyle.
I like living in the future.