you notice the difference when sailing over really rough ground, the Y frame tends to float

But of course you have to now tune the chassis to the pilot a lot more.
Remember hiko found clemcos Y frame almost unsailable as it was tuned to clemcos weight. if you build too flexible it could slow you down , too stiff and the yacht might tend to suddenly trip over itself . Y frames on minis are really science by experimentation. Kind of landsailing cutting edge art

We havent even started trialing any OTT chassis's yet.
On a smooth surface , like lefroy a Y frame might not give you an advantage, then again it might................
note the high degree of mights, maybe's and possibly's in this post