Speaking from experience, the insurance you purchase does not cover anything if you wreck the car. My uncle died in an accident while he was renting it, he bought the normal insurance but not insurance if he wrecked it.
Apparently that is a seperate fee with most car rental companies and they try to sell it as an add on. My uncle skipped over that thinking it was unnecessary even though it was only an additional seventeen dollars. When he passed the company billed his estate the entire amount of the car and fees. The military lawyer that was handling everything negotiated with the companiy and we were told it was taken care of.
Take the time to ask about those add ons. My uncle didnt think he would need them, most people don't expect to be hit by drunk drivers while traveling but it can happen.