Basically yes. You can’t usefully put a car into one of “crashes” or “doesn’t crash” categories the way you can with e.g. what colour an M&M is, or whether Drug X did or didn’t lower blood pressure in a patient, so miles travelled is a reasonable metric.

It’s possible you might be getting hung up on notions of sample size having to be above a particular fixed number and therefore miles sounding like a cheat, but actually there never has been a universal “correct” minimum sample size; it all depends on the data.