I have used both and I'll give my 2 cents.

Why CEX?
It has the initiative user experience that we're already familiar with coming from web2 applications like Facebook, traditional banking apps etc. The main goal of a CEX is to provide ease of use and a seamless trading experience so you don't have to worry about all the blockchain and crypto native stuffs. You can just on-ramp via a number of payment methods like credit card or direct bank deposit.

Another bonus is that, you don't have to worry about security as security is only as strong as the CEX security itself.

So 2 key takeaways for CEXs => Easy to use and relatively secure with a caveat: you've to submit your KYC data with most exchanges to enjoy those benefits.

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Why DEX?

It simple — most of the responsibilities like security and experience is dependent on your blockchain/crypto knowledge or technical know-how. You don't immediately see the benefit of using DEXes but you start to enjoy them after you get the hang of it. For instance, you can become an LP on DEXes and make money with your capital as opposed to CEX where you are limited to fixed fees and you can't become a market maker unless you have some requirements that affords such privileges but that's a story for another day.

DEXes are open and permissionless for everyone but security risks are still available because there are still smart contract risks as well. But overall, it's going to be DEX for me.

Yesterday, I made around $70 providing liquidity to the fake-ish argentine meme coin. I didn't buy the memecoin but only provided 1-sided solana liquidity with it on meteora and earned over $70+ in fees in around hours from $100 deposit. It's only possible on a DEX.