On one side that's a typical writer's error; on the other side it's the compromise of grabbing attention vs telling a meaningful story. First of all, games like Baldur's Gate 3 have to sell. And obviously, Dragons, Tieflings, Vampires, Mind Flayers might grab attention.
But yes, if you only have one-of-a-kinds, then you are running into the weird situation when your "ordinary" farmer's girl collecting flowers in the woods suddenly becomes something special and unheard of.