Generally speaking it allows the mast
itself to be lighter, reducing weight aloft. Single
spreader rigs needs sturdier (and therefore heavier) masts.
Some rigs have doubles (or triples, or even quadruples) because of in-mast furling
as well. And of course in mast furling
adds a lot of weight aloft (the gear
, plus the fact that when the sail is reefed or doused it's not down on the boom).
So it could be "performant", or it could not be. Multispreader rigs can pump and wobble a lot more too, and are trickier to tune.
No solid advantage one way or another but you won't see a lot of race
boats with single spreaders.