Like Anon, I defer to Sam Morningstar. And Sam has another outstanding response to this question, buried in this comment thread:
It even has maps!
- Name recognition
- Perception Cherokee were more “civilised” than other Indian tribes
- Longstanding contact with whites
- Felicitous accidents of skin pigmentation 🙁
- Larger area of Cherokee land claims, extending beyond where Cherokee lived; so lots of white people had nominal contact with Cherokee when they moved in