I do. Not exchanging exciting messages with some secret group of revolutionaries but I've been getting encrypted real time notifications of any account movements from my bank for over a decade.

And I'm a big victim to the note-taking pattern of "mail to self" and that gets a huge feature boost if you can do encrypted mail to self. I like it as my main secrets store because it's almost natural there to add a layer of mild obfuscation to your PINs and the few major passwords that get this treatment.