One more thing is that you do not trade tokens at Binance DEX, but trade b-tokens, at the rate of 1 b token to 1 real token. In order to exchange your b-tokens for regular tokens, you need to come to CEX in any way. This is all done in order to increase the rate of bnb.
Does this apply to all tokens or only to BNB tokens? Is people really required to go through Binance CEX before and after using their DEX? In any case, and based on the information provided in this thread, I would say that their DEX will be just a non-custodial exchange.