How each one actually works
On a CEX you deposit funds to an account the exchange controls. Trades happen in the exchange's internal database and only touch the blockchain when you withdraw. That is why they are fast and cheap to trade on.
On a DEX you connect a wallet and sign a transaction. The swap happens on-chain against a liquidity pool or an on-chain book, and you never hand custody to anyone.
The trade-offs side by side
- Custody — CEX holds your keys; DEX leaves them with you
- Access — CEX requires identity verification; most DEXs do not
- Liquidity — CEXs are usually deeper on major pairs
- Listings — DEXs list new tokens far earlier, with far more risk
- Cost — CEX fees are predictable; DEX costs include gas and price impact
- Recovery — a CEX can reset your access; on a DEX nobody can
Which risk are you taking?
They are not the same risk, and it is worth being explicit about which one you are accepting.
A CEX exposes you to counterparty risk — the venue failing, freezing withdrawals or being hacked. A DEX exposes you to smart-contract and user-error risk — a bug, a malicious approval, or a swap into the wrong token contract.
A practical split
Many users do both: fiat on-ramps, large liquid trades and recurring buys through a regulated CEX, then withdraw longer-term holdings to self-custody and use a DEX only for what a CEX will not list. The rule that survives every cycle is that funds you are not actively trading should not be sitting on an exchange.