* Exceptional Auror: Moody was one of the most respected and skilled Aurors in the wizarding world. He had an unparalleled reputation for catching dark wizards and witches, and his knowledge of the Dark Arts was extensive.
* Expertise in Defense Against the Dark Arts: Dumbledore was looking for a teacher who could effectively prepare students for the dangers of the wizarding world. Moody's practical experience and understanding of the dark arts made him an ideal candidate for the Defense Against the Dark Arts position.
* Security: Dumbledore recognized the growing threat from Voldemort and his followers. Moody's vigilance and paranoia, while sometimes frustrating, made him a valuable asset in protecting Hogwarts.
* Fear Factor: Moody's reputation for ruthlessness and intimidation could deter any potential dark magic from attempting to infiltrate the school. Students, while initially intimidated, respected his abilities and knowledge.
It's important to note that Moody was not the real Alastor Moody, but an imposter: Barty Crouch Jr., disguised with Polyjuice Potion, infiltrated the position. This was part of Voldemort's plan to control Hogwarts from within.
Therefore, while Dumbledore had sound reasons for hiring Moody, he was unaware of the imposter, making his choice tragic in hindsight.