And by abstracting out of the car, you get to skip re-running acceleration/skid/crash tests, redesigning for the particular size/weight/balance signature of the new tech, retooling the lines to manipulate the thing, rewriting/testing the controller code to drive the damn thing, etc.

And perhaps most importantly: you avoid compromising a technology's best efficiency curve in the quest to meet the demands of the driving model.

e.g. even if you're burning fossil fuel to generate power, for whatever reason, there are vastly more-efficient ways to do it than the way we do in in-car ICEs. Those ways just happen to be ill-suited to the power-demands of personal vehicles.