Thing is, Trump isn't doing this because he gives a single shiny shit about women. We know this.
It's not a long-term victory because Trump is pushing the "trans rights are just like gay rights" angle that trans activists, falsely, have also been pushing (except Trump's angle adds "...and we oppose gay rights, too"), and that ultimately does women no favours at all.
On the other hand, in the short term, this does (accidentally, from Trump's point of view) give a shirt=term measure of protection to women in the US penal system, which is at least something.