Recently I came across an article about the future of decentralized exchanges and how they are going to transform the centralized exchanges. One thing that clearly mentioned is that decentralized exchanges are secure and impossible (kind of) to hack as no central entity is running/controlling them. However, I heard about the security breach of Bancor and waves DEX. So what's the point of decentralized exchanges if they are still being hacked 
Where did you hear about security breach in Bancor and Wavesdex ? i like to know more.
So far what i know, the hacking cases were happened in centralized exchange only.
Decentralized exchange like Forkdelta is nearly impossible to hack just by knowing the eth wallet of Forkdelta.
Except it is an inside job i think.