Today its cheaper to buy a whole microwave oven than the ignitioncoil, which would require grid transformer anyway. And the ignition coil will get destroyed with few watts of power, because it's cooling is very bad (it's filled with asphalt).
Older automotive coils were asphalt impregnated. Newer ones are epoxy potted. Some new automotive engine designs have a coil plugged directly onto the spark plug, so there are no plug wires.