"A free paladin has no master. Instead she travels all lands, and in every place takes up the cause of the unarmed and defenseless. You swear fealty not to a lord, but to yourself─you are nobility amongst adventurers." - Jenlyns, in the very first Paladin quest: "Paladin's Pledge"
Additionally, I only mentioned the situations where their brief reprise as an off-tank comes into play. Raid tanking isn't a set "OT does DPS, MT tanks most of the fight" situation, it never has been. The OT in this game spends their fair share of almost every fight tanking, soaking attacks with the MT, or dealing with mechanics that the MT can't due to lack of resources, the risk being too high, or the enemies being too strong. You lead the charge regardless of your role in that fight in particular, you just may not always be handling the boss directly depending on the situation, which is fine.