What Octane do you use?

So when crude oil was first distilled (think: Edwin Drake), kerosene was the desired product since it was cheap heating oil. You're right, everything else was just dumped. But slowly, uses were discovered for the other cuts; naphtha being the precursor to gasoline was discovered to be the best fuel for the early combustion engines. In this case, necessity wasn't the mother of invention. Rather, it was invention was the mother of necessity.