Aside from the obvious positive implications self-driving cars will deliver to the driving public (naps in the driver's seat, binge-watching Twin Peaks on your way to and from Twin Peaks, etc.), one pro possibly outweighs all others: safety.
According to a research paper by McKinsey & Company, driverless cars could save upwards of 300,000 lives per decade in the US alone, and reduce car accidents up to 90% by mid-century. That's 29,447 human lives saved per year in America.
The Atlantic, reporting on McKinsey & Co.'s paper, determined the life-saving ability of driverless cars "...are on par with the efficacy of modern vaccines, which save 42,000 lives for each U.S. birth cohort, according to the Centers for Disease Control." They also note that automotive accidents claim the lives of an estimated 1.2 million people worldwide per year -- meaning that driverless cars could in theory save 10 million lives per decade across the globe, and more than 50 million lives in a half century.