Minecraft wiki entry for Skeleton_horse_farming, associated text: While farming skeleton horses are tedious, skeleton horses are one of the fastest rideable animals in the game, and they are one of the few mobs that heal themselves after being injured, albeit very slowly, which means if you accidentally hit it you won't need to worry about healing it using potions. You can ride them underwater without them bucking you off, which allows underwater transport, however they are hard to obtain, so being able to farm them is handy, especially for SMPs and servers.