This is not a fair comparison - Tesla is comparing miles driven by their systems, which are inherently limited in scope to "easier" scenarios (only lane assist/only on highways/ect), against total US average, which includes _all_ gnarly road situations.
As per the company, a Tesla with FSD Beta engaged experienced an airbag-deployed crash about every 3.2 million miles in the last 12 months. This makes the system about five times safer than the most recently available US average of 600,000 miles per police-reported crash. It should be noted that FSD Beta specifically works for inner-city streets, which involve tons of edge cases and unpredictable driving behaviors from other vehicles.
