But emails are widely understood AKA: "Vanity domains are a very small minority of nerds. Email addresses have the widest common understanding by the average internet user." Decades ago email addresses were a very small minority of nerds, fax machines had a wider common understanding. Email addresses are a more well established technology, just like fax numbers used to be before that, and home landline phone numbers before that. Each was subsequently eclipsed. Email is simply the current such transitional legacy technology.