I mean, at this point, majority of the balance in exchanges are for traders doing daily trading. Majority of Hodlers? I'm pretty sure they would've realized now that they might as well just put it in a hardware wallet instead of leaving it in an exchange, which has been emphasized for oh so long.
a safe way as well as a concern if the wallet containing Bitcoin is lost, the secret word is not properly guarded. withdrawing Bitcoin from Exchange is a long-term goal. But what's the harm in keeping it on an exchange and not traded, is it at a loss? and if it is lost it will be the responsibility of the exchange, but if it is stored in a hard wallet and is lost, only you are responsible.
so which one is more effective and safer when securing your Bitcoin?
No, it's not the responsibility of the exchange. Heck, Bitcoin is basically an asset/coin that you yourself manage. Leaving it to the exchange means that you trust them enough to leave it to them, so even if it was lost, it's not their fault but rather yours. Crypto is called your own personal bank for a reason, it's because everything, from security, to storage, to means of buying/selling/transferring it is all on you.