If I tell you I'm playing a Warrior-nun of the Raven Queen, why does it matter which set of mechanics I use to support that? You have what you need to know, lore-wise.I strongly disagree. If PCs don't reflect the setting at large, then you aren't really playing in that setting.
If I tell you that I'm playing a Paladin, and that doesn't tell you anything about who my character is or how they act, then you've just squandered the rich history of fantasy tropes. We might as well be playing a sci fi game, at that point.