Important part of Eberron, awesome race, game needs a second small race. :P
Thematically enjoyable, important part of Eberron, seems like a waste to not include them in the one setting where they are an independent race/have a dragonmarked house, etc.
Just like them, no real reason beyond that.
In a world like eberron, their demonic heritage is just cooler to me than in FR, so it seems like a waste to not include them in such a setting.