Charisma affects Paladin spells your other main Paladin-specific abilities:
- The number of spells Paladins can prepare (not cast) each day
- The attack bonuses and save DCs for those spells
- The bonus given to nearby allies through Aura of Protection (at level 6)
- The sacred bonus applied to your weapon from Sacred Weapon (level 3)
- (Likely) Healing from Paladin abilities like Healing Radiance(?)
Spells like Command and Compelled Duel (and Nature's Snare maybe?) that require an enemy to make a Saving Throw are less likely to be resisted if you have high Cha. However, as a Paladin, you'll likely rarely cast spells that call for enemy Saving Throws, and even more rarely cast a spell that is a direct attack roll.
Paladins make attacks with only Strength, **unless** they've cast Sacred Weapon on yourself, which
should allow the stacking Cha+Str on to-hit rolls with that weapon.
If you find yourself attacking normally each turn (and Smiting), you'll probably want to increase Str or take a feat. If you find yourself always using Sacred Weapon, healing abilities, and/or other Saving Throw Spells, then you might want to increase Cha.
