The ego is a construction that grows more and more rigid with time until it becomes a prison that stops you from exploring and growing. Like a house full of valuables that you can never leave because you have to guard it against thieves.
Ego death, in a magical sense, is a transformation, a temporarily transcendence from self-centeredness, a way of cleaning out bad habits, misconceptions, etc, that bog down the mind, before the inevitable resurrection as a (hopefully) better person follows.