Dragons could be used as a weapon, where a Pegasus could be a better transportation system because it'd be like Victorian times, riding your horse everywhere, except your horse is
Plus, they can be used as weapons. Unless they hoove each other and other people to death, I suppose.
I really wanted unicorns, but I wouldn't be able to interact with them anymore. Unless they work on technicalities. We're going to need you to define 'virgin' a little better, Unicorns.