That's why I mentioned measurements not vanity sizes. Give me waist, hip, and in-seam in centimeters or inches and let me filter by picking ranges. That's infinitely more useful than gendered S/M/L "sizes".
Vanity sizing means the items is listed as a smaller size than it truly is, changing the units doesn't change anything. They can still say its 28" when its really 30".
No it is not. You would end up getting styles aimed at the wrong gender..