What better alternatives are there?

Even if you prefer vi for interactive edits, I still prefer ed for small edits.

Then there are times when your terminal is borken (or as somebody mentioned, perhaps even your keyboard is broken), this still happens more often than you think.

Recently I had to use some ajax-term thing which was just awful and completely unable to run vi properly for who knows what reason, anything that depends on curses can not be considered reliable.

But more importantly it is the standard and portable tool for scripting the editing of files.