> if you're SSHing into a server to fix a problem, it's possible that /usr/bin/emacs won't be there
You don't need emacs on a server. TRAMP is built-in and can open remote files in a local instance over SSH, SMB, FTP, ADB, or docker/podman.
You don't need emacs on a server. TRAMP is built-in and can open remote files in a local instance over SSH, SMB, FTP, ADB, or docker/podman.
EDIT: Found http://www.fifi.org/doc/tramp/tramp-emacs.html which mentions that TRAMP started development in November 1998. I would have been getting that advice in late 1997 or early 1998, given when I started my Unix class at college. So the answer appears to be that the advice was actually correct at the time, but superseded sooner than I thought it was.
Of course, if your problem is "/usr won't mount", then it's likely that the ftp server isn't running either, so the advice still makes sense.
As an extreme example, today I needed to combine parts of two files into one and decided that
cat foo bar > foobar && mv foobar bar && vim bar