The problem with self-awareness
There is a serious difficulty with using self-awareness and the preference to stay alive as criteria for full moral status.
Young babies, people in comas and people with certain types of brain defect do not show these characteristics. And this means that these 'marginal' human beings deserve less moral consideration than other human beings, and even than some non-human animals.
Most people would regard this as a totally immoral idea, and would want to reject the theory that leads to this conclusion.
The easy way to solve the problem is to cheat and put human beings in an even higher moral category, and simply state that even human beings who aren't self-aware and have no preference to go on living should be regarded as deserving full moral consideration.
This is speciesism, which, despite much criticism, is a perfectly coherent moral position to take.