Its not an argument. Its a discussion.
Well like your analogy,the art student always displays his first work.And it is obviously novice. But through it being displayed the audience,teacher,helps him in improving his art. (in magic,that being the reactions and what/how the audience say what they say)
Which is tons more efficient than the student drawing home alone and just keeps drawing and drawing and will never know what is wrong or how he can improve.