CEX are mostly use for trading that is why they might have more liquidity than DEX, aside from that they have no advantage over DEX.
CEX is very poor in terms of security due to their selfishness, they wanted to be in control of all their users' funds which makes it easier for them to go with the funds anytime they want
CEXs provide a lot of advantages over DEXs, most of them convincing users due to how convenient they are. DEXs are way less easier to use and sometimes even require a little more knowledge to use than your average CEX. If DEXs were as easy to use as CEXs, everyone’d use them.
Poor security for CEXs isn’t caused by selfishness. It’s just that there’s pretty much no way to create a CEX that’s non-custodial, provides liquidity, so many trading pairs, the quickness of a CEX, customer support etc all while still being non-custodial. It’s either they go the tough route and provide less advantages than a CEX and simultaneously their profit drops too, or they just follow the typical business model and offer users the best user experience but you’re not in control as much anymore.