The interface of sftp is largely the same as ftp. You can give someone an sftp client, username, and password and they wouldn't be able to tell the difference.

The interface of sftp is largely the same as ftp. You can give someone an sftp client, username, and password and they wouldn't be able to tell the difference. A new e2e protocol that works just like email does would be excellent, but we don't yet have that. Signal &co are chat apps with a different feel and purpose and other than matrix and xmpp not federated, which is a non starter for many entities.