In real life, a 5 minute gas fill-up and a 15 minute charge are approximately equal. You don't have to wait at the charger like you do for gas, so it can charge while use use the bathroom and buy a coffee.

But unfortunately 20-80 is only 3-4 minutes faster than 0-80, just over 25 minutes give or take a few minutes depending on temperature etc. Like cell phones, car batteries can charge a lot faster when they're empty.