The super fast cats lose this and its because of the speed and the speed they lose during maneuvers: they're so fast that when you have to throw in just one extra tack or jibe, your competitor is moving so fast and you lose so much momentum, you basically lose the race. On a monohull, you can keep the momentum from tack to tack and benefit from the shifting wind directions. An analogy (over simplified): catamarans is like a drag race, monohulls is like f1 race.
You can also look at it on the flip side, A mono hull appears to not loose momentum in a tack because it never really gets going fast in the first place
There is a bucket load of skill and tactics required to get these things around a course, it is just different and you gota think quicker because they don't take all day to get to the other end of the course like other forms of sail boats.
All these sailors on these boats all sail and have sailed monohulls, ask them after this contest what they prefer to sail!
These guys are having the blast of their life