BITCOIN is well tested for safe transaction making, but the only thing that prone for hacking is on what kind of application wallet you used to stored bitcoin because i think hacker do prefer to try to hack the site of different application wallet which involve currency savings.
Hackers are not only foccusing on wallet or any other money related stuffs because hackers are also active on hacking social media accounts , forum accounts , and government related websites .
Bitcoin on the other hand is safe . the risk of using it will only depend on the user if what safety measure he or she is using .
storing your coins on a hardware and offline wallet is also helpful to secure your coins more evenly .