No, you don’t need a Coinbase Wallet to invest in cryptocurrencies on the Exchange. Sign-up for an account and buy/sell cryptocurrencies in US dollars or other fiat currencies from the Coinbase app. You can securely store your cryptocurrencies on Coinbase just like any other financial asset like stocks. However, if you’d like to keep custody of cryptos in your wallet and manage them with your private keys, download the Coinbase Wallet and store them securely.