Miniature horses were bred at one time to pull coal carts in the mines, because obviously they can fit in places where regular horses cant, and they are very strong. My son and daughter both work on a mini horse farm. The owner raises and sells them all over the world, so I know some of them are pretty costly as she has had buyers visit her here from other countries. She has a couple of stallions that have a few world champion trophies; I think mainly for conformation. She has a lot of tiny saddles and bridles for them but never seen her show so don't know what all they do at shows, but pretty much a lot of the same things that bigger horses do. It is fun to go to the farm and watch them; the babies are miniscule when they're born and the stallions toss their heads, rear and gallop around and act studly, just like their big counterparts. I personally wouldn't want one, but I think they are very interesting and have their own place in the horse world.