I have used 4 of the 85,000 point certificates, and for 3 of them have booked rooms worth over $600 per night. I used one certificate for a $400+ room, when my travel plans for the rest of the year didn’t include better options. I typically pair them with another night or two on points.

The inability to use FNCs to book higher room categories limits their usefulness a bit - you generally have to be willing to take one of the cheapest rooms - but as a Titanium I have been lucky to be upgraded on all 3 of my past FNC stays. For my upcoming 4th FNC stay, the hotel offers 3 different categories of rooms for the same number of points, even though at paid rates the rooms vary in cost by up to roughly $150, so I was able to pick one with the view I wanted. I wish more hotels did that.

Like the prior poster, I’ve used them as part of a longer trip I’m planning to take anyway, and have gotten the most value out of using them in Europe, rather than the U.S.