I think making it a Feat allows for an Android to "pull a Data" and learn emotions/empathy over time, as opposed to Traits that can only be taken at chargen, but I could be wrong about Traits only being allowed at chargen. If I were GMing, I'd keep the Charisma requirement, but allow it as a Trait, reflecting the character growth prior to play. But if a player wanted to take it as a Feat during play, I'd remove or reduce the Charisma requirement.