[Bozos of Bones]

What's so damn special about horse controls? You go forward, you go backward, you turn and you jump... What's there to like?
Plenty to not like tho. They're clunky, slow, stupid, frail and get stuck on trees alot(I kid you not, my Shadowmere was once stuck on a tree after I dismounted to clear a gate).
So, to summarize the line of a developer "Hey let's add horses, they're cool!" and does exactly that, with no added planning, skills(no horsemanship that guides your speed, horse health or god forbid mounted combat) or importance. As WOLFGIR said, they're here for the screenshots.

As for storing things IN them... I did not need that mental image. Now, every time I go read GRR, I'll remember that demonic child and stuffing stuff inside a horse... DAMN YOU!