We have to remember that the Commedia dell'Arte was the first theater structure having "real female" participants among the acting troupe. Usually one.
Of course these women (in the beginning were prostitutes who couldn't perform their profession because of the Church's regulations ...) were not experienced at all in acting.
Up to that moment, all stage acting had been made by men - in female clothes when necessary - so the women in the troupe would need some time to catch up.
But we can imagine (and this is my personal assumption) that they could provide that little break/entertainment the Caratterista would make, singing or dancing, no need to be witty or to learn stories, nothing to do except some animation, some fun, for the excitement-hungry audience.
And in those times having a real woman onstage - dressed or less dressed - was already a huge innovation.
