Physical theatre is not just about acrobatics. The benefit of training for an actor is that he becomes highly aware of his body and gets a sense of precision and balance, which cuts away the clutter of unnecessary movements. This makes his/her presence resonate powerfully on stage.
In traditional theatre, you train in a form for many years, and once you become a master, you break the form and therefore you find independence as an artist. In conventional theatre, you begin free but later get bound by your own patterns or the director’s, losing autonomy as an actor.