Trims and Armor stands for horses and nautilus

So, I'm the kind of builder who likes to use armor stands to make my builds stand out and I just thought about It, why do only players have armor stands and trims? It makes sense why wolfs don't have it because they use armadillo scute but horses and nautilus have ore based armor plus a horse armor stand would be a really sick way to add horse statues in your worlds I'm not sure how much use the nautilus stands or trims would get, but I believe that they both would act like normal armor stands or trims I just thought It would be a cool and awesome way to bring some more life into the world kind of like how I use copper golem statues as Minecraft's version of garden gnomes