As an interstellar carrier it's perfect though. Boost a limited-duration (aka small mass) craft at unsustainable acceleration to dock with an interstellar tran

As an interstellar carrier it's perfect though. Boost a limited-duration (aka small mass) craft at unsustainable acceleration to dock with an interstellar transiting ship, then detach and decelerate on the other end. All the while you're able to continue increasing the interstellar ship's velocity. Limited only by the max velocity you can feasibly intercept. By being propellantless, it essentially takes mass considerations out of the interstellar transit system (given enough time).