What's the point with that quite lackluster story in Endwalker?

[CrownySuccubus]

One of the big gripes i will always have with the story is despite how much they preach about light and dark not always equating to good or bad is that they never ever have us use darkness during the msq. It has consistently been light light light. Why even make it a point of dark not always being bad if you aren’t going to have any of the main protagonists use it?

To be honest, I really did think it was weird that they specifically made the ShB intro demonstrate that nothing worked against Sin Eaters besides Dark Knight power, but then that never comes up in the game. Like, I get it -- they can't lock out everybody except that one class, but it still would have been cool if Warrior of Darkness became more than a title.