Ego is who I am. Without ego, there is no I.
PsychonautWiki describes ego death as memory suppression. And it's an interesting way to look at it and I think it is true. Without your memory, there is no you.
In my thoughts, everything is dependent on perspective and many of the experiences we have are experienced through the perspective of our ego. If we take that away, we get completely new experience that we were not able to experience prior.
Similar to how switching of channels in a radio works, perhaps we can tune into different frequencies of consciousness. In any way, it's quite hard to put these concepts into words, if not impossible.
The value of ego loss is primarily in self analysis. The social constructs that normally limit your thinking, and beliefs, are lifted. It allows for a free flow of thought that can only be attributed to your being. At least that's my thought behind it. I primarily use psychedelics as a learning tool, not expecting to learn anything larger about the world or universe, just hoping to learn more about myself.