Hmm is it 100% safe? No dont think so. You never know what will happen to the exchange. I can shut down or be hacked etc. On the other side if you look at bittrex binnace kucoin i dont think the chance is likely they will get hacked or that they will shut down. In that matter you are never 100% safe. My advice would be dont put all your funds on a exchange and best thing to do is put it on a desktop wallet or a cold wallet. Those are safer then leaving your funds on exchange.