I'm a Plat that stayed at an Autograph and a Fairfield property within the last week.
I used OLCI for the Autograph - my room wasn't ready at 4pm when I had chosen that time during my morning OLCI, and I got a not-so-great room. My parents (Gold) skipped OLCI, arrived at the hotel with me and got upgraded at the desk.
I skipped OLCI for the Fairfield - I was able to check in early and the desk upgraded me on the spot.
It's a small sample size, but I am not using OLCI until Marriott proves that there are benefits to the customer.