This aspect is covered in the article. Sure, you will control the private keys, but in order to trade i.e. Bitcoin you will have to hand in the REAL BTC to binance for custody, and you will get a BTC-stablecoin on Binance chain that your private key will control.
What I am worried about with this approach is things like
Users of GUSD still control the private keys - they just don’t control the collateral that is USD. Does this make sense to you?
I am 100% that Binance DEX will be popular, and I am saying that as a competitor and decentralization advocate. I still think that calling it a DEX is a lie and shady marketing, and that real DEXs can have their UI and economics improved to a point where they are safer, easier and more profitable to use than and centralized exchange, including fake DEX.