User blog comment:Angel of death 77/Bethesda developers creating new content for skyrim/@comment-4781674-20120213201542/@comment-4058895-20120215144314

If you need to travel to an area that you have not yet, then a horse is useful regardless of whether or not other NPCs use them, If you play on higher difficulties or your a low level then travelling on foot can be dangerous if you come across a cave bear or a snow sabre which can easily kill you on low levels so a horse can be a great help to outrun these enemies or to act as support if you wish to fight them.