I think this is incorrect. When I review the Chase Sapphire Preferred benefits document, under the CDW section it states:

"You are covered when Your name is embossed on an eligible card issued in the United States, and You use Your credit card Account and/or rewards programs associated with Your Account to initiate and complete Your entire car rental transaction. Only You, as the primary renter of the vehicle, and any additional drivers permitted by the Rental Car Agreement are covered.

I called the Chase benefits line and they confirmed this as well. So, if I use the Chase travel portal associated with my CSR card and use UR points for the car rental booking I get the same CDW coverage as my CSR card.