The reason why I mainly believe that bitcoin is the safest system here in crypto world is that since I was introduced to cryptocurrency life I have never hard of bitcoin wallet been hacked all like Ethereum, Binanace exchange and lots more. It's the security in bitcoin that boost it price since the holders believe that their funds are safe and secure the hold it for long instead of dumping it and the price keep growing.
Sorry to break it to you, but Bitcoin exchanges have been hacked for billions and billions of dollars in BTC total. People get personal wallets hacked too of course, if they are weak on security.