Couple of years ago DEX wasn't much popular than right now. People couldn't use it properly because lack of liquidity. That's why many DEX died also. But After Uniswap rise the whole picture is change about DEX exchange. Many promising DEX also coming now days which have lots of liquidity, volumes and much security like Uniswap. The way Uniswap going, i wouldn't surprise if it will take place over Binance.