Yeah, exactly. Cup size can change a lot about how clothes look, and they can even change the perceived personality of the character. Smaller boobs make a character look more innocent (I kinda want a really small-chested Miqote), and combined with the right hair, boob size can also make a character seem educated without going nerdy (Imagine a large-chested Elezen with a clean cut hairstyle and spectacles). It makes much more of a difference than anything purely sexual.