There's a lot of hacking of these exchanges going on lately. Coincheck exchange in Japan got hacked for millions of dollars in NEM a few days ago. These exchanges need to get their security together. And just when I was planning on registering with KuCoin. SMH. IMO, it's more secure to store your coins in an off-line wallet. But if you're day trading or swing trading coins, it can become an inconvenience and costly to be transferring coins between off-line and exchange wallets.