Men would still on average out perform women in most categories, making it very difficult for women to get to the top of the chart. High ELOs would almost exclussively be men and thats where the media focus and attention would be on, drowing out some of the top women atheletes in lower ELOs. In a system where the highest ELO wins a medal or something i think it would be less fair than having gendered ELOs. Something like amateur or beer league sports might benefit more from genderless ELO but i think it would be controversial for pro athletes.