I think bitcoin has good security system.Hacker are beside here to hacking our bitcoin from our wallet or many kind of exchange.Because they want to get bitcoin without any hard work.Hackers and scamers are provably target the exchange system to hack.we should don't use our wallet in a exchange for long time.If any one have to effort a hard ware wallet, that will be great.Otherwise they should keep there wallet and privet keys only his responsibilty,thank you.