To me, I think Centralized exchanges are more user-friendly than DEXes due to which people don't like to visit their websites while they can do all the trading on a CEX app like Binance, Kucoin, Hotbit, etc. and that's the only reason why DEXes don't have much volume. Most of the DEXes I've seen are mostly based on Eth smart contracts, but I believe that Eth itself is Centralized so how can those DEXes be called as decentralized ones?
but if you keep all your assets for too long at the exchange place it will pose a very high threat to you because the place of exchange can inadvertently collapse and there will be many assets that cannot be liquidated and held at the exchange place, there have been many cases it happens like that, so I think you should be able to be careful when storing assets in an exchange place.