The auto insurance by the credit card company is ONLY secondary.

The primary insurance is your own car insurance. More than ten years ago, a drunk driver without valid insurance hit my rented car from behind, my own insurance paid the whole bill; and the credit card company paid ZERO, though I reported the accident to them.

If you were involved in a big accident and your own auto insurance were not enough to cover the damage, the credit card company would play a role in this kind of situation.