One word of warning -- though the CC Company offers the insurance - it is secondary not primary coverage.
Example: A customer rented a vehicle - left it in a parking garage for drop off. Several days later they were notified there was a "ding" on it. Cost - $ 224.00 - Customer put the claim into the credit card company (AMEX), who promptly paid the bill. HOWEVER - after they paid the bill, they subrogated back to the customers own insurance company. Since the insurance company is primary - they reimbursed AMEX's payment.
So... if you have NO claims on your own auto policy - I would rely on the CC coverage ..... but if you have multiple claims on your own policy and a tickets - take the CDW.
PM me if you have additional questions -- I'm in the insurance biz.
FYI - if you don't have a personal auto policy - just use the CC since it becomes primary since you don't have a policy.