I agreed with you, it is just a way CZ boosted Binance coin and the popularity of Binance in crypto world. If community ask for DEX, Binance can provide it, that is the main purpose of CZ. He want to demonstrate that Binance is very adaptable to hot trends, and demands of crypto community. Indirectly, he also want to spread the strong dedication (with continuous initiatives) to help Binance maintains its first position among crypto exchange. In my opinion, if Vitalik is a pure technical experts, Charlie Lee is a two-faced man, CZ is a very smart, flexible and adaptable CEO.