Yes, for an individual but for an exchange or trading site it is not. Hacking can only be a problem if you have no knowledge about security. Just look at banks that also operates digital transaction but the hack is only between the users and not inside the bank itself.
But if you get into the bank and use their computer you can hack them, very system have a flaw and almost every system can be hacked, one way or another.
But why to worry about it, if you ate afraid then don't keep your money there, use some offline wallet and you will be safe from hacking, buy if someone point a gun into your face you will be forced to give him your offline wallet, that is the some kind of hack too.
Don't live in fear from bad things, they can happen to anyone anytime, there are ways to protect yourself until si point, use that, be smart and avoid traps and you will be fine. Even if something bad happens don't fall into despair, learn from mistakes and keep your head up.