Comment by chuckadams

Nothing says "prompt interactively" like Ctrl-U. I mean, it literally stands for "universal argument", which is basically "do this command, but different". Defaulting to "insert four times" because why not? Mysterious :^)

Like I said I used emacs for a quarter century, wrote quite a bit of elisp for doing my job, and I still miss some of those things, but I've made do with perl scripts. I still pop up emacs for quick edits now and again, but I long ago gave up trying to force it into the shape of a full-blown IDE.