In our recent BCA regional event the "elite" bracket included every entry with a fargo rating 600 and up. There were 52 entrants. I didn't try to find the average fargo for the field but I can assure that we have a lot of very sporty players in the mid to upper 600s who played.
The event was won by a legit 606 with a lot of robustness who has been around a long time.
Fargo probably would have given him less than 1/10th of one percent chance to win the event using their math, systems and algorithms. Probably close to zero within the margin of error. But he won it. By winning 8 matches he was the dog in all but one. Many of them a huge dog.
With over 4k robustness he's now a 611. Still lower than almost every single opponent in that event.
Here are the actual results entered into the Fargo calculator.
View attachment 898720
So I don't buy that it is deadly accurate predicting winners and this was a two day event not a single match.