Now they're forcing the exchange of currencies and the withdrawal from there bitcoin and altcoins. Why? Because bitcoin is an anonymous currency that is not managed by anyone and is fully decentralized. On the one hand it is good, and on the other it is our weakness before hackers. Hackers will not be able to find, after stealing bitcoins from the exchange.
some weaknesses still arise in smart contracts, it can be seen that exchange markets such as bancor and binance have even suffered heavy losses from the coins connected to them, but over time, they also certainly do not want to repeat the same thing, by doing the system rigorous treatment and can often reduce the impact of cracks that can be penetrated by hackers.