Obviously this won’t work for all sports, but things like football, track, soccer, it would allow for de-gendered team, even allowing athletes with the skills but not the genetically-endowed physical attributes to have a place to play.
Note: I know very little about sports and being on a sports team, so please point out anything that doesn’t make sense.
Honestly, once they’ve gone through HRT, nearly all, if not all the advantages given by their sex are reversed. I’m not sure how well that works for the F>M athletes, but the M>F athletes are the ones where HRT not working properly would be a problem, and they’re the ones that would unbalance things if not properly transitioned.
Except that isn’t true. Men are more stable due to hip width, their hearts move more blood, their arms and hands are larger/longer, and their lungs hold more air. None of that goes away.