To do much more than out out an electrical fire CO2 has to be huge. Something you roll, not something you carry. If you have a significant fuel load like A and B fires you pretty much have to flood the flame with CO2 and smother the fire, along with the normal cooling you get with CO2.
Back in the real olden days we had computer rooms with CO2 flooding systems (AEC in Germantown had one) but I was never sure if this was fire protection or intruder control.
