why is self-awareness usually discussed as something profoundly mysterious and advanced?
Because “self-awareness” is sometimes used to mean “consciousness”, which is indeed mysterious (nobody knows what it is—if they did, less would be written about the question of what it is) and advanced (nobody knows what an explanation would even look like).
And “self-awareness” is also used to mean “having any sort of model of oneself”, which many simple machines have—a fairly trivial sort of thing. If one does not notice that the same word is being used to mean two different things, one mysterious and one mundane, the resulting confusion can be mistaken for even greater profundity, mysteriousness, and advanced thinking.
Because “self-awareness” is sometimes used to mean “consciousness”, which is indeed mysterious (nobody knows what it is—if they did, less would be written about the question of what it is) and advanced (nobody knows what an explanation would even look like).
And “self-awareness” is also used to mean “having any sort of model of oneself”, which many simple machines have—a fairly trivial sort of thing. If one does not notice that the same word is being used to mean two different things, one mysterious and one mundane, the resulting confusion can be mistaken for even greater profundity, mysteriousness, and advanced thinking.