With amiibo cards, you can bring in other villagers and assign them roles, too, replacing the villagers that are randomly in there. So it's really just a question of aesthetics and creating your own little visual story.
You could pretty much follow this logic and ask what is the point of the Animal Crossing series altogether. It's just for fun! Although I think I would have had so much more fun with this if all of this 13 years ago... Oh well.