Commedia dell’Arte is sprung from a time long before circus and theatre were divided as separate genres, when all sorts of stage disciplines could be played on the same stage without one having to be better or more refined than the other. Therefore all sorts of disciplines were incorporated in a Commedia dell’Arte performance, like dance, acrobatics, music, fencing, stilts, juggling etc.
They are either user to move the action forward or to highlight the show. Just like the singing and dancing in a musical. There is a danger to use different kind of disciplines as stop in the show just to show off.
The same rules apply for most disciplines. They come into the performance as a part of it either they are there to amplify, aestheticize, tell the story, stylize a scene, create an atmosphere, crack a joke or just is there for its own sake. This goes for tight rope dancers, fire artists, animal trainer, yoyo artists… all disciplines that can be used in Commedia dell’Arte.