You need to learn about wallets first, wallet like coinbase are online wallet meaning they keep your private key safe for you, this means you don't have 100% control of your wallet, for me I don't recommend such
That's why we shouldn't use centralized wallets, preferably decentralized wallets, and we have complete control over our address. Go to myetherwallet and create an address with and store your private key as carefully as possible
to be honest centralized wallet serve its purpose as a mere temporary way to store your erc20 token or just simply to exchange it but people are free to save their token there and to be honest it's still relatively safer if you don't know whether your PC is secured or not. It's all jus depends on the people.