I am in the Unnecessary camp. Unless there’s a particular reason to call out my gender identity and its relationship to what I was born with, why bother? How else will we ever get to the point when it’s a non-issue in general?
While we are at it, let’s just call trans women what they are: women. After all, there is no reason to call out my gender identity in relation to how I was born except to other me and to single me out for some kind of abuse.
On the other hand , if you feel that “cis” is not needed but “trans” is, then it might be a sign you are arguing in bad faith. See James Finn’s response above concerning the correlation between those who don’t like the word “cis” and those who don’t support trans people.