The big advantages to horses are that it's a lot easier on the rider, and that you can carry more stuff. I mean, if you give me the choice between walking 20 miles carrying 50 pounds of gear and riding that distance, I'll take the horse. If that's harder on the horse than it would be on me, I can live with that. And since I rarely walk 20 miles at a time, the horse is probably better at it than I am anyway.