If we comparing centralized & decentralized exchange both of them have their own ability, but the reason why centralized always more get attention from decentralized exchange because the volume it self. Decentralized exchange have a small volume if we compare with centralized exchange, also not everyone want really get a fully control of their asset maybe a bit lazy. Centralized exchange also have a good UI Design, went decentralized more bit complicated about the platform than centralized exchange.