Centralized exchanges take too much fees and community based projects do not have much funds to spare so they kinda never get the attention they deserve. Secondly, decentralized exchanges have more security compared to centralized ones.
But most exchange now are centralized like Bittrex, Binance, Okex, coinbene, that requiring KYC. Then I also believe that Decentralized id more secured because you're the only one who is able to control it and have access on it. But sometimes there is risk like Etherdelta or Forkdelta this platform is an example of decentralize exchange but its not good for me because this platform is asking private key and eth address too, and faced issues several times in terms of hacking the account of their client users. In short, I would rather choose centralize exchange than decentralized exchange. And besides, most of the top 10 exchange was centralized exchange too.
this is exactly the biggest problem that decentralized exchanges are facing: people prefer to stick to centralized ones and don't use decentralized exchanges! at the same time they expect a perfect solution!
well that won't work because if you and I don't use them, they won't improve because they need to be tried out so that the bugs can be found or at the very least they can improve their platform using our suggestions. not to mention that the volume won't go up as long as everyone sticks to centralized exchanges while getting scammed by them!