For those just knowledgable enough to be dangerous.
You're looking at pellets in the 100s of gram range accelerating a vehicle 150 000 bigger. Force = Mass x Acceleration so at 30Km/s and 0.1Kg you get a force of 3000N. By Newtons 3rd law on a body of 150 mt that's about 0.02 m/s, or about 0.002g.
So no people won't be tripping over each other. The fact it runs for 3 days might have been another clue that would not be happening.
The short impulse does make it a shock load but the same could be said of the explosions in the cylinders of a car (which this somewhat resembles).
NIAC is low budget, high risk investment into potentially game changing technology .and they've actually done phase 1 of this. All other fusion proposals have come from a fusion power background where breakeven and electricity generation are key goals. They dumped these and followed the analysis. From their PoV wrapping a fusing plasma in a series of magnetically driven foils (IE thin sheets <1mm thick) is actually a good thing as it gives them more reaction mass to push out the back.
Note they still have not generated fusion which I think is a pretty big point but if they do that will be a bargain. As for a 200KW PV array keep in mind the ISS array while big is several generations behind the SoA in PV cells, either mult junction or using solar concentrators.