No worries. Good question. I may be wrong, of course - I'm not anything to do with making such decisions, but as far as I could gather, it's primarily for customisation.
When I say neither should look out of place, this doesn't mean "recreate only the original sprites", but to try and replicate the art style very closely whilst allowing players to be black skinned, or blond haired, or wear many types of armour / clothing which are not currently in the game, without having to manually edit 10,000 odd still frames by hand - and to do this so closely that they could stand next to a 2D Brahmin or shopkeeper and it would still look completely normal.
Recently, longhaired man and bald man were added, but these must have been manually adjusted frame by frame, for every action and every type of weapon. Currently, some NPCs can't use some weapons, and the Merchant Party leader will always run with his arms in the air like a scared child etc. If these were all 3D models, these things could be adjusted / fixed by applying new textures or animations to the models - cutting such a change down from weeks and weeks of work into days of work.
As I said, I may be wrong, but that's my interpretation of it.
