The problem with email is "most emails are unencrypted". Only the transmission over SMTP is mostly encrypted worldwide. So the ones who owns the MTA can eavesdr

The problem with email is "most emails are unencrypted". Only the transmission over SMTP is mostly encrypted worldwide. So the ones who owns the MTA can eavesdrop the contents. The mail content encryption, GPG/OpenGPG/PGP are not widely deployed, (complex setup for non tech users), and even in that case, the headers are not encrypted. This is the gap Telegram, Line, Blackberry (partially) have filled over the years.