My problem with "cis" is that it provides justification for treating women badly.
Here's the Stonewall glossary: www.stonewall.org.uk/help-advice/glossary-terms
Trans: an umbrella term to describe people whose gender is not the same as, or does not sit comfortably with, the sex they were assigned at birth.
Gender: often expressed in terms of masculinity and femininity, gender is largely culturally determined and is assumed from the sex assigned at birth.
Trans covers a lot of people these days, not just transsexuals. It certainly covers me (am I FUCK comfortable with the culturally determined assumptions made about me from my sex at birth). It covers all of those feminists described as TERFs. It covers every woman who thinks that the culturally determined assumptions of their era are bullshit - from the Suffragettes to anti-porn campaigners.
And it redefines women - "cis" women, "real" women - as being those who ARE comfortable with cultural constraints. Which means that we're back to those constraints being innate in some way
which provides ample justification for continued oppression. Women are oppressed because of culturally determined gender, with which "cis" women IDENTIFY. If you don't identify with it then you're not a woman at all.
I'm a lesbian (the short-haired hairy-pitted type), and this isn't the first time I've heard "you're not a real woman" "what sort of woman are you" etc. It's just that now we call this "progress."