You need to just read a little on Voltage versus current. Kind a like the difference between pressure and volume in a fluid system. They are not the same, but they are related.

Think of a wire rating. Current determines the size of the copper. The voltage rating is based on the insulation. It is current that charges the coil. Voltage is the potential that pushes the current. No voltage, no current, no path to complete circuit no current. Disconnect the ground wire on the coil that goes to a point system and turn on the ignition and measure voltage. You will read 12 at the + and negative terminal, yet there is no charge in the coil to fire the spark plug. It is current that creates the magnetic field in the coil that collapses and creates the High voltage that fires the plug on the secondary side. That is high voltage low current. Can't create or destroy energy in a system. Think transformer. Which an induction coil IS NOT, but a CD system behaves that way. Your talking apples and oranges.

There are better coils made GM made them. They can charge faster and endure the higher current charge, but they are bigger. The faster the coil charges the higher the rpm the motor can go.

The ignition is a system and all the component in the system see the voltage and current. Why do high current draw system on your car have replaceable relays vice just operate off the wire directly? There is an optimal current that the points can absorb without rapid wear. There is an optimal current the coil can handle without overheating, all to create an optimal high voltage at the plug of about 15 to 20 thousand volts that can jump a spark plug in less-than-optimal conditions. Cold, bad fuel fouled etc..., at an rpm of less than about 5200. That is the point system. The initial Electronic was about the same rpm, because they used the same coil, you just eliminated the wear and adjustment of points/gap.

Jumper the ballast an run your car. The coil will over heat and become erratic, before the points wear, but keep changing coils as you burn them up and you also have to change the point rather quickly because they have burned away also.

The ballast protect the coil but also establishes the max current that the points can handle with a reasonable wear per time.