Complex sentence: Character theories are popular with academics teaching and researching media and film studies as they are useful for appreciating the structure of different types of media and the roles of the characters, fictional or otherwise that are portrayed in them.
Split into simpler sentences: Character theories are popular with academics teaching and researching media and film studies. This is because they assist in the appreciation of the structure of different types of media and the roles of the characters, fictional or otherwise that are portrayed in them.