It's the same reason people are using SQLite for their startup's production database, or why they self-host their own e-mail server. They're tech hipsters. Old stuff is cool, man. Now if you'll excuse me, I need to typewrite a letter and OCR it into Markdown so I can save it in CVS and e-mail my editor an ar'd version of the repo so they can edit the new pages of my upcoming book ("Antique Tech: Escaping Techno-Feudalism with Old Solutions to New Problems")