Actually, it may be a feasible driver of mass while not being a feasible weapon. If it takes something the size of 5-6 refrigerators to generate the particles, but they (+fuel) could generate the equivalent of >6ish refrigerators worth of our presently used fuel, it would be feasible for transportation.
For weapons (I was thinking grenades and bombs) you would need to have smaller sizes, and it would have to be efficient to make the particle generators themselves. Spacecraft (at present) can be one-off designs. We could conceivably make a very expensive, reasonably lightweight, reasonably energy-efficient, reasonably large antimatter drive once while being unable to use that technology to make a reproducible superweapon.
For weapons (I was thinking grenades and bombs) you would need to have smaller sizes, and it would have to be efficient to make the particle generators themselves. Spacecraft (at present) can be one-off designs. We could conceivably make a very expensive, reasonably lightweight, reasonably energy-efficient, reasonably large antimatter drive once while being unable to use that technology to make a reproducible superweapon.