I see at least one big advantage to cisgendered girls competing in these instances and with respect to being recruited or drafted to a higher level.
Such competitions are apparently newsworthy, so there'll be more attention and eyeballs on the event and maybe a greater chance of becoming aware to and then observed and noticed by a recruiter/scout.
In something like a swimming competition, the times are the times. So is each swimmer's skills and technique. If next-level opportunities simply came down to who won at a lower-level event, then recruiting/scouting would be a dead industry. And in something where there's direct competition like basketball, I have faith in recruiters and scouts that they can still correctly note a girl's rebounding ability even if that one game is against a larger center.