DEX is developing day by day, it is true that there has been progress recently but inadequacies are still many. Honestly, to provide services like CEX, I would say never DEX can do. I've never traded P2P on any DEX, but I wonder how they can prevent scams if they don't control the users. If you trade on centralized exchange, once scam happens, exchange will lock your account and force you to verify your identity but that can't happen on DEX. I am curious.
DEX is not the same as p2p as the transaction goes through a smart contract of an exchange. So problems could be mainly in case if a corrupted smart contract. Swap exchanges accumulate trading pairs provided by users so tokens for a trader are held by exchange. But I'm sure we'll see some new decisions for even better service. I don't know which, may be they are not invented yet, but we are still in the very beginning.