is there a point to using Royal authority in your pally rotation?

[Reinfeld]

Enmity doesn't matter.

If you are 1 point of Enmity above everyone else, it's the same as if you are 1,000,000 points of enmity above everyone else.

That's not entirely accurate because you need at least some buffer between you and the next line. On something like PLD whose damage combo doesn't have any enmity bonus, it's possible for DPS to generate enmity faster than Royal Authority.