Why an email alias?

Hey guys.

99% of the posts I read on the subject always ask about technical aspects of email aliases: how to set them up, if I can use them for X service, of "what if I have an issue with X email alias", or what if I lose it.... Etc etc etc.

But none of them question the WHY it is recommended to use them, or why it might not be necessary, or why it even matters. And again, I've …

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