FWIW.....a couple somewhat random points....
I have never owned an F3A biplane. I have observed many, and from my observations, only been interested in flying a few. Most definitely having a bipe is a way to get attention...whether it flies better or not (attention is not always a good thing). I've yet to see a bipe I NEED to have. Of the bipes I've flown, I have not been compelled to buy one. When / if possible, I would like to have a flight on an Alferma.
At the 2015 US NATs, AC had his Allure and his Passion bipe. Chip had his Allure and his Finals Touch bipe. Both planned to use the Allure for the prelims and "save" the bipes for the finals (2015 US NATs had midair potential prior to the finals). Chip split the 2 rounds in the semis between the Allure and bipe, and several people commented to Chip that the Allure looked better. Chip liked the bipe better, and flew it in the finals and finished 3rd. AC stayed with the Allure and won. I was in 2nd with my Allure, winning the last unknown which was very knife edge intensive. Post contest, a number of the judges said what really stood out in the last unknown was the quality of my knife edge maneuvers....hmmmm......
CPLR and have both tried bipes....and both choose to fly monoplanes (or "1.5s"). Right now, there is only 1 Alferma....maybe Brett would fly the Alferma in the prelims if he had 2 Alfermas. My opinion is that for the overwhelming number of pilots, the differences between a top level monoplane and top level bipe are going to be pretty close to insignificant, especially when you consider just how few pilots ever fly unknowns in competition. Maybe most pilots fly what they like?