Appearance is absolutely the best skill in charisma.
The reason is simple:
1: It gets you some of the best jobs possible in the game at the moment.
2: It is also useful for offensive duels, which happen when you want them to, giving you more options, vs tactics which is only useful when your opponent attacks.
The only fallback of appearance is that if you choose appearance as your primary stat, while you will quickly rank your way up to Evangelizing for experience and trading with Indians for money, you will quickly find that between the levels of 20 and 50 you will have severely limited your options if you focus only on Appearance.
Appearance is good in a rush to Evangelizing then switching to other skills
Or by playing a character up to level 70+ and then switching from everything else completely to Appearance as quickly as possible. Obviously this requires a ton of money. I have considered doing it myself, but I have elected not to for one simple reason: I want Robbing Trains, and that requires shooting and not appearance. So I will be raising my shooting until I have Robbing trains at around labor 10, and then I will switch to appearance. I have some in Appearance now, and have had between 10-40 in the skill, but it is necessary to pull them out of appearance to build up for robbing trains. Appearance is one of those skills you will find yourself putting skill points into, taking them out, and putting them back in.
All in all it is based on your preferences, but heed my words. IF you choose pure appearance 100% of the time and never stop, you will not grow in exp or money as fast as a player who mixes it up.