Leaving your body behind and realizing it is just the house for your consciousness helps you become unafraid of life and death. since most people are afraid of both (to varying degrees) it can be extremely helpful to have that confirmation that your soul goes on when you leave the body.
For most people, astral projection is just interesting, possibly fun, possibly scary, and definitely thought provoking. I wouldn't say any human NEEDS to do it since it is not really part of the living process, but it is cool nonetheless. And if you intend to be an astral warrior, fight evil, and kick some demon ass, then I'd say it's essential to master it.
