A kid I coached dove for the high school team for 4 years and made the finals at NCAA championships as a freshman. A number of swimmers I know have done the same. Some were grateful for that experience as it was a much more team-oriented setting than if they had only competed on the amateur circuit. There’s no single right path.One kid in my neighborhood got scholarship to play tennis for UCLA and he has never competed in HS tennis, only USTA and UTR tournaments. His UTR is 13.3 and the best player on the tennis team in his HS conference has a UTR of 7. It would not be a fair fight.
For what it’s worth, I’ve also seen some of these swimmers/divers lose meets to kids who didn’t even make the state championship. Sometimes people have an off-meet whether due to injury or off-course distraction, and a full body of work needs to be considered rather than basing decisions on one event. Coaching is freaking hard.