Here's what I came up with. But now, they're used in every game genre. Because characters give the game a human-interest component. And they permit gamers a degree of empathy. Compelling characters are an essential part of movies because compelling cinematic narratives always contain an empathic component.
Games are the same way.
The better the main character, the more the player is drawn into the action. But I don't really mean plot because, to me, that word implies something linear. A game doesn't have to have a narrative, but one with a narrative is always more compelling than one without. As with everything in life, the more I put into a game, the more I get out of it. While investment has always been a defining characteristic associated with RPGs, that is changing now.