For a strictly pleasure day boat for use in the midwest where light winds are the norm, which is better? Does the cat rig work well enough? Does the sloop rig have a big advantage if sail area is kept pretty close on both rigs?
I believe that cat rig is more efficient than a sloop if everything else is equal.
Properly designed cat boat is as fast or faster than similar sized sloop.
If we are talking small boat/daysailer, there is no single reason to have two sails unless one wants to keep crew busy.
sunfish, laser, finn, Moth, A-class catamaran, etc...
As boat and sail(s) grow, handling become a problem and second sail (or mast) become justified.
And yeah, I race Nacra F17 and cruise in Freedom 28 Cat Ketch.