I think that they are a doubled edged sword. Yes, they are a great place to start your refing journey as they are (typically) a safe environment to develop, but at the same time I think they set unrealistic expectations for referees just starting for example cards being discouraged and a lack of exposure to different types of game situation. IMO there is nothing wrong with them if you are aware of this difference between academy and Sunday league football, and I would be happy to do academy game if and when I can!