The decision to include a more casual way to play Fire Emblem was met with skepticism initially.
The team behind Fire Emblem Awakening discussed the implementation of the Casual mode and the difficulties behind making such a decision in a recent developer interview.
When the idea was first brought up, some of the team members were against the idea. However, the team realised that many people were intimidated by the series because of the fact that party members die permanently. Adding in a casual mode where players do not have to worry about such a consequence has meant that more people are willing to try Fire Emblem. Although they did also acknowledge that some of the fun of the series is in the possibility of losing a much loved character, the consensus was that both play styles have their advantages and that is why the mode was implemented.
While the team thinks that they will still implement a casual mode in future games, the director from Nintendo, Genki Yokota, gave a hypothetical example for an instance in which not having a casual mode might be beneficial. "let's say we wanted to depict a really big and serious war scene. In a situation like that, having permadeath would help lend weight to everything; it'd be much more tense and meaningful to players if their characters' lives were truly on the line, just like in a real war. So it really depends."