Marriott emailed members to announce that it will discontinue the Points Advance feature on March 28. Previously, this feature allowed you to book an award stay even if you did not yet have enough points, as long as you earned the required points within 60 days after booking or at least 30 days before check-in. Reportedly, Marriott believes relatively few people used this feature, so it is being removed.
Personally, I think quite a few people probably used this method to lock in award availability as soon as award rooms were released, then later either complete the booking with the same account or quietly cancel and rebook with another account. After this feature is gone, award nights at some popular hotels may become a bit easier to book. For ordinary Marriott users, that is probably a good thing as well.