It's a mile driven by the car, not by a human. An easy concept to understand, unless you don't want to understand it.
If you want to play the "ultimate goal" game, the ultimate goal is to do it all profitably at scale -- and Tesla is way ahead on that front, which is why their fleet self-drives almost as much per day as Waymo's fleet has ever driven.
Time will tell, but anyone who can't make a case for both "Tesla wins" and "Waymo wins" scenarios is a fanboy with deeply compromised thought processes.
If miles driven by cars under human supervision counted, Toyota cruise control would clock the highest. Autonomy is a binary: it’s either driverless or it’s not. There’s no need to invent terms such as “self driving mile”.
Tesla may be profitable, but nowhere close to a working solution. So how far ahead are they really?
Tesla's system is so fragile it needs a human ready to take over at any second to prevent a crash. Compared to Waymo Tesla FSD is like a kid using training wheels.
Driverless miles: Waymo 20M, Tesla 0
Self-driving miles: Waymo 20M, Tesla 2000M