Why do doctors prescribe Ambien when it makes you hallucinate even at small doses?

Like even at the recommended dose, most of it i don't remember, but apperantly i was very out of it and what i do remember was the flowers started dancing, all the words were moving, a man had 3 legs, there were too of the same girl, and my book shelf started rearranging itself. that's what i remember, which isn't much.