Oil was about kerosene and lighting → heating → automobiles.

Cars were its killer app. They enabled the density of a city (commute in and commute out). They even changed people’s self identity - cars today are an avatar of who we are - a status symbol.

Critically - Oil was not only an energy producer but also an energy storage device - it was a battery.

Oil was kept in tanks as a battery. To this day it is one of the best batteries, with no leakage of charge!