I had the same kind of questions a few days ago as never before I saw the rates or hotels that did not allow to redeem points. I had the discount with points window popping up in EACH single booking. It seems that with the new loyalty program this has changed and there are a LOT of exceptions and blackout dates/rates... I am Diamond but I already decided to move a lot of bookings to Marriott this year as I see the loyalty program of Accor being worse instead of introducing improvements.