As much as I mistrust USDT, they have more trading pairs and a lot more liquidity than the BUSD. That makes it more practicable for trading
Binance strongly supports its stablecoin and if you have a free BUSD, the exchange provides an opportunity to get passive income. FFor trading, I used BUSD when the USDT problem wasn't solved yet. Now I mostly trade coins in pairs to USDT, because this stablecoin has high liquidity.