It is wisest to have a secure wallet, because if you accept payments in a secure wallet and want to sell it, you can of course sell it on an exchange, which will cost you a small fee. Kucoin exchange has disabled withdrawals for thousands of people, but in my opinion, it should never be used as a wallet or exchange.
Exchanges are exchanges and they are places for trading, not to hold your bitcoins or altcoins as your assets. People mostly forget about purposes of exchanges, that is trading and trading. Staking on exchanges is another big mistaken practice from people who have altcoins. By staking, they lock their altcoins on exchanges while nobody knows what will happen with those exchanges in the future, next weeks, next months or next years.
Events made you scare about custodial wallets, centralized exchanges.