I'm a little wary of not showing any message if file is not found. But I could put the error in the status bar, or i could make a #filecontentsi command that is similar but ignores error..
You're right that is probably better. A new #filecontentsifexist (or something like that) would be useful.
One thing I use #filecontents for is to add a status/notification text line in some alias results. For example imagine an alias with 3 alternative backup commands as result. We can with #filecontents add an extra result line that reads a textfile generated by one of those three commands last time it ran. So the results can look something like:
backup command b1
backup command b2
backup command b3
Last run: b1 2018-02-15 success