I see it, I haven't used binance for a long time. Only the mobile app is still installed and it doesn't show the benefit points like the wider view version. Have you proven it is free or at least cheaper when compared to the spot market? I see they also enable price slippage.
I tried some CEX and all the platforms I used have this feature with the same name. You need to search for it and it provides a simple exchange without fees and at the same price as Bitcoin at the moment you click on the button. However, it is instantaneous and you cannot sell at a specific price or choose the exchange rate. Either you agree to the price or reject it.
I don't think the market for DEX will vanish even if CEX implements most of its features.
If the bills are passed in their current form, all DEXs will require users to complete KYC, so I assume DEX will be limited to p2p.