Maybe It is because most winners are smart people who know that it is not a good idea to share their user name on a public forum especially when everybody can see how much they are making.
I really don't think anybody cares how much anybody is making.
One of the reasons why dices sites like wolf.bet and luckydice.com among others provide a leaderboard and daily race is to give the other players a chance to flex.
Realistically, I dont think anybody is going to bother searching for users on BTT to beg for money. After all, there are plenty of millionaires on the forum, some of them very public. Surely they would be stronger targets?
Everything is already anonymous no matter how hard you do brag but people around cant do anything.
Thanks for the update!