I truly see no benefit. When I book with Accor, my experience at check-in is that I go to the front desk, give my LCAH card or my last name, sign that I am myself, get the keycard and go to my room. It usually takes me a grand total of 90 seconds, including some friendly banter with the Front Desk staff if they are nice.

Sometimes they ask me for the CC if I haven't paid in advance and/or they're fussy about the minibar (in the latter case I usually look them in the eye and make them check my history with Accor). This adds 15-30 secs, and I feel more secure and comfortable doing it at the front desk than on the go on my mobile. Moreover, quite often even if the hotel has my card details (I have a guaranteed reservation), they still somehow need to ask me for the card to block the required amount.

I see this all as a way of extorting the credit card details for unguaranteed reservations to charge it if you fail to appear before 6 PM. I enjoy the freedom of arriving when I want and cancelling at the last moment, and I am not willing to give it up for free. If they offered me a confirmed upgrade (or free breakfast, or something else of actual value) in return, I am all in, I can even pay a few days in advance for a non-prepaid rate.

Or if the hotels are in operational mess because of too many non-guaranteed reservations, they should make it harder and/or more expensive to book non-guaranteed rates (e.g. available only for LCAH members and those with a business contracts or something).