Why is transgender even a thing? Either you're a woman or a man. Obviously say if you were born a man but want to be a woman, then you're a woman not transgender and vice versa.
Maybe when being trans won't get us murdered and when we can use a damn washroom we can talk about this. Until then, no, the term transgender is very useful and it's only because cisgender people come from a position of privilege that they can say it's useless.
So if you are cisgender, you are actually just male or female? Why can't we just be that? Why do we need that special label? Being a woman has worked fine for me for 72 years. I see no need to have that changed. I understand, if you are uncomfortable in the body you were born in. If your body is male, but your phyche is female, or vice versa, needing to get comfortable with whatever you are or become. I do. I get it. And needing your special gender specification,I get that too, but I am just a woman. And I am fine with that.
Being cisgender is having the same gender as the gender you were assigned at birth. It's a term that has been around for quite a while but you won't find it if you're not reading about trans issues a lot.