It certainly makes it the best "personal" card for car rentals, especially in places where your auto insurance does not cover you at all.

(Increasingly, credit card coverages including but limited to Diners are starting to balk at "loss of use" charges and/or "administrative fees" on rental claims, so if you have a claim in a locaiton where your auto insurance would cover it, it may come out roughly a wash between your deductible and what the credit card coverage won't cover that you have to negotiate yourself with the rental company.)