As many users before me have said, centralized exchange are not completely secure, whatever their promises to their customers. Don't trust all your funds to an exchange, it should be in your wallet in the long term. Even though we believe in some exchanges, but basically we have to remain responsible for our assets there. This means that we accept any consequences that may occur, good or bad are the consequences.
~snip~
Exchanges should be used to exchange, not to store your Bitcoin.
Buy bitcoin there, then send to your own wallet, that's the only way to truly known you just bought real Bitcoin, and not some fake IOU
People that keep their "bitcoin" in exchanges are always in a position in which they can lose all that money overnight.