One of the worries if you are using centralised exchanges, is that they can mandate what they do to your coins. As you said, they can lock your account for no valid reason. So it is better to own your wallet with your own private keys and such. At least you have the full control of your funds and you don't have to worry that the exchange will get it from you for no reason.
Besides getting control of your private keys, you'd need to follow some necessary security precautions in order to avoid many undesired situations in the future. A non-custodial or decentralized wallet is not a "golden pill" that will solve all of your problems. While it's much safer to store your crypto this way than using centralized wallets, you'd still need to keep an eye out for malicious actors in cyberspace. As long as you take responsibility of securing your funds properly, nothing should go wrong. For true security/reliability of large crypto balances, it's recommended to use a hardware wallet at all times. Otherwise, you can lose your hard-earned money as a result of software issues, bugs, etc.
Nonetheless, there's nothing we can do to make people use decentralized wallets on top of centralized ones. The vast majority of people prefer centralized wallets on top of decentralized ones because they're extremely easy to use. There's no technical knowledge involved when using a centralized wallet other than knowing the basic stuff (sending/receiving crypto and inputting public addresses). Despite the high risks of storing crypto on centralized wallets, they're still popular in the mainstream world. Ordinary people will continue to use centralized wallets for mainstream crypto transactions, while the rest will use decentralized alternatives to reduce risks as much as possible. It's rather a person's choice from one type of wallet to the other. Just my thoughts