The concept of BinanceDeX with BSC is of course much different. BSC is far superior to BinanceDEX. Every token developed from the Ethereum blockchain is also contained in the BSC, and vice versa. So even though ethereum fees return to normal, the BSC blockchain continues to run normally.
The BinanceDex exchange is just an additional option from Binance for those who like to exchange coins in an easier and faster way, because it is still very possible for the ERC20 network which until now there are still some people who use it.