The irony lay in that email addresses were originally designed as communication channels (like snail mail), but have since been co-opted into serving as a uniqu

The irony lay in that email addresses were originally designed as communication channels (like snail mail), but have since been co-opted into serving as a unique identifier (like SSN). So, you need to share your email address to be able to communicate properly, but you also need to hoard it because it is part of how you identify yourself. Aliases are one workaround but are not universally accepted as identifiers.