The more positions a player knows to play, the more valuable he/she’ll be to the team.
A high percentage of youth players who became professionals played in a different position to the one they made full-time careers in.
The benefits for young players playing in different positions are massive. Developing game understanding is a vital part of the education of young players, the best way to learn this skill is to occupy different areas of the pitch.
As an example a full-back will usually have the game in front of him and on his inside, a midfielder will have the game behind him, in front of him and either side, players will only ever learn the patterns of play by being responsible for that position. Sometimes letting the star striker play in defence will be beneficial for his development and needs, this may affect the match result, but as a coach or parent, you have to see the bigger picture.
The longer-term outcome for the team is anyone can be asked to go and play a variety of positions in a range of systems without worrying. When it comes down to it, a player who can play in different positions and play well in each one is more valuable to a coach than the player who can’t.