I definitely agree that they fall under the same umbrella, but there’s still nuance there. binary trans people are still trying to fit into the gender binary, while nonbinary people are usually either rejecting it completely or wanting to be in between. I think that the experience of “I want to be a woman, not a man” and “I just don’t want to be a man” or vice versa are different enough to make a strong distinction between them, even if they both fall under “I am not my AGAB”.