To answer it in simple words, the need to download Metamask Extension arises when the investors is willing to manage their wallet through a web plugin instead of a mobile app.Coinbase Pro Sign In is an advanced feature of Coinbase which is also available as Advance Trade now a days.Recovering a Coinbase wallet without a seed phrase can be a challenge, but there are still some steps you can take to try to regain access to your funds. https://sites.google.com/helplogln.com/metamaskextensionn/ https://sites.google.com/cryptowaletusa.com/coinbasewallet/home https://sites.google.com/helplogln.com/coinbasepro-signin/