Not just searchability, auto-categorization, and anti-spam as well. I would view it through the lens of putting the power of choice in the hands of the user. I

Not just searchability, auto-categorization, and anti-spam as well. I would view it through the lens of putting the power of choice in the hands of the user. It allows people to make the choice of whether they value privacy more than usability, or, it allows fine-grained control -- end-to-end for messages you care to keep private, but no encryption for the mails you don't care about, but want searchability (mailing lists, notification emails, package tracking, etc)