From the purely technical point of view, it would even be feasible to send e-mails directly from the sender's SMTP customer to that in the recipient. Having said that, the usage of an SMTP server has a transparent advantage: if the receiver’s inbox server is chaotic or quickly away https://www.upwork.com/services/product/development-it-migration-to-magento-2-nodejs-in-new-vps-server-aws-linode-digitalocean-1445680653983371264?ref=project_share&tier=0