제3자 사이트를 통해서 결제를 해도 신용카드에서 제공하는 렌트카 보험 혜택을 받을 수 있나요?

안됩니다. 
가능할 것 같습니다. Priceline이나 Autoslash도 Car Rental Agency라고 볼 수 있으니까요. 확실히 하시려면, 체이스에 문의하시는 것이 제일 좋겠네요.

CSP Benefits Guide page 4에 보시면 다음과 같습니다. 

What’s Not Covered? The Auto Rental Collision Damage Waiver benefit does not apply to: •  Any obligation You assume under any agreement (other than the deductible on Your personal auto policy) • Any violation of the auto rental agreement or this benefit •  Injury of anyone, including you, or damage to anything, inside or outside the Rental Vehicle • Loss or theft of personal belongings • Personal liability •  Expenses assumed, waived or paid by the auto rental company or its insurer •  The cost of any insurance or collision damage waiver offered by or purchased through the auto rental company •  Depreciation of the Rental Vehicle caused by the incident including, but not limited to, “diminished value” •  Expenses reimbursable by Your insurer, employer, or employer’s insurance •  Theft or damage due to intentional acts or due to the driver(s) being under the influence of alcohol, intoxicants, or drugs, or due to contraband, or illegal activities • Wear and tear, gradual deterioration, or mechanical breakdown • Items not installed by the original manufacturer • Damage due to off-road operation of the Rental Vehicle •  Theft or damage due to hostility of any kind (including, but not limited to, war, invasion, rebellion, insurrection, or terrorist activities) • Confiscation by authorities • Vehicles that do not meet the definition of covered vehicles •  Rental periods that either exceed or are intended to exceed thirty-one (31) days • Leases and mini leases •  Theft or damage resulting from the authorized driver’s and/or cardholder’s lack of reasonable care in protecting the Rental Vehicle before and/or after damage or theft occurs (for example, leaving the car running and unattended) •  Theft or damage reported more than one hundred (100) days* after the date of the incident •  Theft or damage for which a claim form has not been received within one hundred twenty (120) days* from the date of the incident •  Theft or damage for which all required documentation has not been received within three hundred sixty-five (365) days after the date of the incident • Vehicles that are not rented from a Rental Agency•  Damage to the interior bed of a pick-up truck unless such damage is caused by or the result of a covered loss, such as theft or collision •  Damage to a pick-up truck that is a result of loading or unloading objects into the bed

저 볼드표시된 문장은 turo같은 서비스에 대한 설명 아닐까요?

오래되긴했지만 doc에 나와있기로는 된다고 하네요

https://www.doctorofcredit.com/car-rental-insurance-are-priceline-rentals-covered-by-the-credit-card/amp/

제가 잘못 생각한 것 같습니다. 
Priceline이나 Autoslash도 Car Rental Agency라고 볼 수 있으니까, 되는 것 같습니다. 

4년전이지만 사프로 익스피디아에서 빌린 차 힛앤런 아무런 문제없이 해결했습니다. 

아멕스의 경우는 아멕스랑 채팅해서 렌트카 보험 커버 된다는거 확인 했습니다. 

이미 다른 분들의 말씀처럼 Turo 같은건 안되고 오토슬래쉬로 연동된 일반적인 렌트카업체/여행싸이트는 됩니다.

댓글 달아주신 모든 분들 정말 감사드립니다. 많은 분들이 된다고 해주셨네요! 하저씨님께서 추천해주신 대로 체이스에 최종 문의 해보고 답을 얻게 되면 공유차 글 업데이트 하도록 하겠습니다.

묻어가는 질문인데 샤프로 체이스몰에서 UR포인트로 렌트카 예약하면 보험 커버되는거죠? 

사프나 사리 카드에 있는 포인트로 결제할 경우에만요. UR 포탈에서 사프나 사리 카드 먼저 선택하고, 체이스 트래블 가서 포인트 결제하시면 됩니다.