It gives no more information than body fat percent. Unless you're already making an assumption about body fat %, muscle %, height, etc, you can't guess someone's weight from the outside.
For the top end of cycling (and probably other endurance sports), things like V02max for top athletes seems be pretty common knowledge already. But I'm not sure how objectively that can be measured if someone is intent on suppressing it to stay in a certain bracket. So height would still probably be more useful, at least for flats.
Imo, either make divisions based directly on factors that matter, which varies from sport to sport but most often comes down to things like height and weight, or get rid of them.