All these days, it was free or zero cost to withdraw USDT TRC20 but suddenly from today, they have changed it to 0.20 USDT. I don't know if BUSD fee was 0 from the beginning or not but now it has been decreased to 0. The target is to boost the use of BUSD. This is the manipulation of Binance. There’s more to come.
Obviously binance is playing some games here and to be honest they are a business so they have the right to earn money too but yes they could have kept trx or trc20 transactions free like before and offered some incentive for busd but they did what suited them the best.