If something is susceptible to attack, it will be attacked. Read “susceptible” as: when the cost of the attack is lower than the loot it yields. Those who believe that moving their bitcoin to an exchange is safer are living an illusion. Custody that isn’t yours is someone else’s custody — and that means inheriting the threat model of custody, plus the threat model of centralization, plus the fact that the prize is far larger. It’s not a matter of if. It’s a matter of when