Automatic updates have a choice of using FTP or FTPS (SSL), but there is no SFTP option. Many of my clients disallow all forms of FTP due to security concerns. They do, however allow SFTP. But WP does not.
This makes updating and maintaining their sites cumbersome and time consuming - as often this involves downloading and copying a number of files into different directories. The potential for error is high. Is there any reason why WP does not support SFTP?
(FTPS and SFTP use different protocols to provide their security layer. FTPS uses SSL or Secure Socket Layer over port 21. The "S" in SFTP does not stand for SSL. It stands for SSH or secure shell, which runs over port 22. It uses less server resources, does not require an FTP server to be running and is a much better security option.)
As more and more ISPs limit FTP access and switch to secure socket layers, I admonish WP to add support for SFTP.