Amusingly, the works of Epictetus we have are because one of his students, Arrian, recorded his teachings.
Stoic philosopher was someone who was living his life according to stoic philosophy. To learn philosophy and to become a philosopher was to enter training program where you live with the teacher and internalize the philosophy as way of life.
Why would anyone read books about philosophy of bodybuilding and how to lift weights for years if they are not going go to go to gym and actually train? In a same way, you can't really become a Stoic philosopher by reading the books.