The private key "locks" your coins to you better than anything that can be social engineered. People were using Gox as a bank account and consequently only were an entry in gox's books saying they were owed a certain number of bitcoins. Encrypting any wallet on your computer is a plus, as is offline cold storage with something like bip38.

Remember, you only own bitcoin if you have the private key, if not, someone just owes them to you and you have counterparty risk. 

:-)